Assembly tool for modular implants, kit and associated method

ABSTRACT

An assembly tool for assembly of a first component of a prosthesis to a second component of the prosthesis for use in joint arthroplasty is provided. The tool includes a first member in contact with the first component and a second member connected to the second component. The first member defines a first member longitudinal axis. The first member and the second member provide for the assembly of the first component of the prosthesis to the second component of the prosthesis. The second member provides relative motion of the second member with respect to the first member when the second member is rotated relative to the first member about the first member longitudinal axis. The first member and the second member have relative motion features adapted to reduce friction that cooperate with each other to provide the relative motion of the first member with respect to the second member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.11/541,184, filed Sep. 29, 2006, entitled ASSEMBLY TOOL FOR MODULARIMPLANTS, KIT AND ASSOCIATED METHOD (now U.S. Pat. No. 8,998,919 issuedApr. 7, 2015), the disclosure of which is hereby incorporated byreference in its entirety. Cross-reference is also made to U.S. patentapplication Ser. No. 10/878,292, filed Jun. 28, 2004, entitled ASSEMBLYTOOL FOR MODULAR IMPLANTS AND ASSOCIATED METHOD (now U.S. Pat. No.7,582,092 issued Sep. 1, 2009), and U.S. patent application Ser. No.10/606,401, filed Jun. 25, 2003, entitled ASSEMBLY TOOL FOR MODULARIMPLANTS AND ASSOCIATED METHOD (now U.S. Pat. No. 7,297,166 issued Nov.20, 2007), the disclosures of which are hereby incorporated by referenceherein in their entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to the field of orthopaedics,and more particularly, to an implant for use in arthroplasty.

BACKGROUND OF THE INVENTION

Patients who suffer from the pain and immobility caused byosteoarthritis and rheumatoid arthritis have an option of jointreplacement surgery. Joint replacement surgery is quite common andenables many individuals to function properly when it would not beotherwise possible to do so. Artificial joints are usually comprised ofmetal, ceramic and/or plastic components that are fixed to existingbone.

Such joint replacement surgery is otherwise known as joint arthroplasty.Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged joint is replaced with a prosthetic joint. In atypical total joint arthroplasty, the ends or distal portions of thebones adjacent to the joint are resected or a portion of the distal partof the bone is removed and the artificial joint is secured thereto.

There are known to exist many designs and methods for manufacturingimplantable articles, such as bone prostheses. Such bone prosthesesinclude components of artificial joints such as elbows, hips, knees andshoulders.

During performance of a joint replacement procedure, it is generallynecessary to provide the surgeon with a certain degree of flexibility inthe selection of a prosthesis. In particular, the anatomy of the boneinto which the prosthesis is to be implanted may vary somewhat frompatient to patient. Such variations may be due to, for example, thepatient's age, size and gender. For example, in the case of a femoralprosthesis, the patient's femur may be relatively long or relativelyshort thereby requiring use of a femoral prosthesis, which includes astem that is relatively long or short, respectively. Moreover, incertain cases, such as when use of a relatively long stem length isrequired, the stem must also be bowed in order to conform to the anatomyof the patient's femoral canal.

Such a need for prostheses of varying shapes and sizes thus creates anumber of problems in regard to the use of a one-piece prosthesis. Forexample, a hospital or surgery center must maintain a relatively largeinventory of prostheses in order to have the requisite mix of prosthesesneeded for certain situations, such as trauma situations and revisionsurgery. Moreover, since the bow of the stem must conform to the bow ofthe intramedullary canal of the patient's femur, rotational positioningof the upper portion of the prosthesis is limited thereby renderingprecise location of the upper portion and hence the head of theprosthesis very difficult.

In addition, since corresponding bones of the left and right side of apatient's anatomy (e.g. left and right femur) may bow in oppositedirections, it is necessary to provide (left) and (right) variations ofthe prosthesis in order to provide anteversion of the bone stem, therebyfurther increasing the inventory of prostheses which must be maintained.

As a result of these and other drawbacks, a number of modular prostheseshave been designed. As its name implies, a modular prosthesis isconstructed in modular form so that the individual elements or figuresof the prosthesis can be selected to fit the needs of a given patient'sanatomy. For example, modular prostheses have been designed whichinclude a proximal neck component which can be assembled to any one ofnumerous distal stem components in order to create an assembly whichfits the needs of a given patient's anatomy. Such a design allows thedistal stem component to be selected and thereafter implanted in thepatient's bone in a position which conforms to the patient's anatomywhile also allowing for a limited degree of independent positioning ofthe proximal neck component relative to the patient's pelvis.

One issue that arises as a result of the use of a modular prosthesis isthe locking of the components relative to one another. In particular,firm reproducible locking of the proximal neck component to the distalstem component is critical to prevent separation of the two componentssubsequent to implantation thereof into the patient. The need for thefirm locking is particularly necessary if the design does not providefor positive locking with weight bearing. As such, a number of lockingmechanisms have heretofore been designed to lock the components of amodular prosthesis to one another. For example, a number of modularprostheses have heretofore been designed to include a distal stemcomponent, which has an upwardly extending post, which is received intoa bore defined distal neck component. A relatively long fastener such asa screw or bolt is utilized to secure the post with the bore. Othermethods of securing modular components include the impacting of onecomponent onto the other. This method has highly variable results

Current designs of modular stems include designs in which the modularconnection utilizes a tapered fit between the two components. Forexample, the proximal body may include an internal taper, which mateswith an external taper on the distal stem. Such a taper connection maybe used in conjunction with additional securing means, for example, athreaded connection or may be used alone. It is important that thetapered connection be secure. For example, the proper amount of forcemust be applied to the tapered connection to properly secure the taperedconnection so that the connection can withstand the forces associatedwith the operation of the stem.

Current attempts to provide a device to adjoin components of a modularjoint prosthesis are fraught with several problems. For example, thedevice may not provide sufficient mechanical advantage to securely lockthe components. Further, the ergonomics available to lock the componentsmay not be optimal. Further, a device relying solely on the displacementfor a taper connection may not provide sufficient force as there may notbe an accurate correspondence of displacement to the clamping force.Further, utilizing a displacement method may make it possible toovertighten and damage the components. Further, prior art solutions maybe difficult to manufacture or expensive to make. Further prior artdevices may be unsuitable for disconnecting the components.

Once a modular prosthesis, for example, a modular hip stem prosthesis,has its relative components positioned properly, the components must befirmly secured to each other. It is possible when the components aresecured together that relative motion between the components may occurcausing their relative position in particular their angular orientationto be disturbed. In other words, when the first and second components ofthe modular hip stem are drawn together, one component may rotate aboutthe other one causing their version or orientation to be compromised.Further, whatever device that is used to angularly position thecomponents of the modular prosthesis into the proper orientation mayneed to be removed and an assembly device positioned on the prosthesisto secure the components to each other. Such removal of the alignmentdevice and installation of the assembly device adds cost and complexityto the procedure, as well as, increasing the operating room time.

There is thus a need to provide for an assembly and disassembly toolcapable of alleviating at least some of the aforementioned problems.

US Patent Application Publication No. 20040122439 entitled “ADJUSTABLEBIOMECHANICAL TEMPLATING & RESECTION INSTRUMENT AND ASSOCIATED METHOD”,US Patent Application Publication No. 20040122437 entitled “ALIGNMENTDEVICE FOR MODULAR IMPLANTS AND METHOD”, US Patent ApplicationPublication No. 20040122440 entitled “INSTRUMENT AND ASSOCIATED METHODOF TRIALING FOR MODULAR HIP STEMS”, US Patent Application PublicationNo. 20040267266 published Jun. 25, 2003 entitled “MODULAR TAPERED REAMERFOR BONE PREPARATION AND ASSOCIATED METHOD”, and US Patent ApplicationPublication No. 20040267267 published Dec. 30, 2004 entitled “NON-LINEARREAMER FOR BONE PREPARATION AND ASSOCIATED METHOD” are herebyincorporated in their entireties by reference.

Prior attempts to provide instruments to assemble modular prostheseshave had problems due to the large and bulky nature of such instruments.These large and bulky instruments are difficult for the surgeon to useand provide problems in performing minimally invasive orthopedic implantsurgery. Furthermore, prior art tools provide a tool designed for onlyone modular prosthesis. The tool may not be suitable for prostheses withother sizes and shapes. The present invention is directed to alleviateat least some of the problems with the prior art.

SUMMARY OF THE INVENTION

According to the present invention, a device is provided for twocomponents of a modular joint prosthesis. The device is particularlywell-suited for assembling the proximal stem component to the distalstem component of a modular prosthetic joint stem, such as one for a hipprosthesis. The instrument has a portion that engages, for example, theproximal component and another component that engages the distalcomponent. The instrument applies force on the proximal component and anopposing force on the distal component. For example, the instrument maythreadably engage the proximal aspect of the distal stem and apply anopposing force on the proximal shoulder of the proximal body.

The first component of the instrument is caused to rotate with respectto the second component of the instrument. A handle is rotated about thecentral axis that conveys rotary motion into axial displacement. Theaxial displacement serves to thereby lock and unlock the taper joiningthe distal component to the proximal component. The instrument may bedesigned to yield a specific axial displacement, which is previouslydetermined based upon the specific taper geometry of the implant.

In an embodiment of the present invention, a coupling device threadablyengages with the proximal aspect of the distal stem. A counterfacecontacts the proximal aspect or shoulder of the proximal body in orderto provide opposing forces, which axially displace the two componentsrelative to each other, thus locking and unlocking the taperedconnection. The instrument may be actuated by rotating one handle withrespect to the body or another handle. The handle may, for example,travel in a slot, angled relative to the axis of the cylinder, therebyproviding axial motion. In other embodiments of the present invention, astandard thread and bolt connection between the first component and thesecond component provide for the axial motion.

According to the present invention, an instrument is provided thatengages and disengages in components of prosthesis by applying opposingforces while offering rotational control to the components. Theinstrument and associated method can be used for assembly,disassembling, and controlling the version of a modular jointreplacement.

The instrument may, for example, threadably engage the proximal aspectof the distal stem and apply an opposing force on the proximal shoulderof the proximal body to assemble or disassemble the components. Theinstruments may also lock onto the proximal component to control versionof the components during assembly.

The instrument may threadably engage the proximal aspect of the distalstem. A counterface, for example, may contact the proximal aspect of theshoulder and an orientation device in the form of a crab claw type ofclamp may be used to orient the proximal portion of the body. Theinstruments provide opposing forces, which axially displaces the twocomponents relative to each other thus locking and unlocking the taperedconnection of the modular joint.

The orientation device and the instruments may be used to provide amethod to control the rotation and or the position of the proximal bodywith respect to the distal stem during assembly. The instrument may beactuated by a rotating handle. The handle may for example, travel in aslot angled relative to the axis of the body of the instrument. Theinstrument may include indicia or marks that can assist in the properangular orientation of the modular components. External data forexample, CT data can be used to reproduce a predetermined angle selectedby the surgeon for the prosthesis.

According to the present invention an instrument and associated methodis provided that can be used for assembling and disassembling a modularjoint prosthesis. The instrument engages the proximal aspect of thedistal stem by suitable means, such as by a threadable engagement, andapplies an opposing force on the proximal shoulder of the proximal bodyto assemble or disassemble the components. The instrument does so withlow friction by the use of a low friction connection.

Such a low friction connection may be in the form of a threadedconnection with truncated roots and crests in the threads. One such formof truncated roots and crests is in the form of an Acme® thread. Othermethods of reducing friction, such as the use of lubricants, coatedsurfaces, or a ball bearing race, may be utilized to maintain a lowfriction connection.

The instrument of the present invention threadably engages the proximalaspect of the distal stem. A face of the instrument contacts theproximal aspect in the form of the shoulder of the proximal body. Theinstrument provides opposing forces that displace the two componentsrelative to each other, thus locking and unlocking the taper connection.The instrument is actuated by rotating handles. In one case the handletravels in a slot angle relative to the axis of the cylinder. In anotherembodiment the connection is in the form of a thread. The thread mayinclude truncated roots and crests on the thread and may be in the formof an Acme® thread.

According to one embodiment of the present invention, there is providedan assembly tool for assembly of a first component of a prosthesis to asecond component of the prosthesis for use in joint arthroplasty. Thetool includes a first member operably associated with the firstcomponent and a second member. The second member is operably associatedwith the second component. At least one of the first member and thesecond member are adapted to provide for the assembly of the firstcomponent of the prosthesis to the second component of the prosthesis.The second member is operably associated with the first member forrelative motion between the first member and the second member forassembly of the first component of the prosthesis to the secondcomponent. The tool also includes an angular orientation featurecooperating with at least one of the first member and the second memberfor at least one of replicating and measuring the relative angularorientation of the first component with respect to the second component.

According to another embodiment of the present invention there isprovided a kit for use in joint arthroplasty. The kit includes animplant for implantation at least partially in the medullary canal of along bone. The implant includes a first component and a second componentremovably attachable to the first component and an assembly tool. Theassembly tool has a first member operably associated with the firstcomponent. The first member includes a first member relative motionfeature and a body defining a generally cylindrical longitudinal openingtherein. A second member is operably associated with the secondcomponent. The second member is operably associated with the firstmember for relative motion between the first member and the secondmember for assembly of the first component of the prosthesis to thesecond component. The assembly tool also includes an angular orientationfeature cooperating with at least one of the first member and the secondmember for at least one of replicating and measuring the relativeangular orientation of the first component with respect to the secondcomponent.

According to a further embodiment of the present invention, there isprovided a method for providing joint arthroplasty. The method includesthe step of providing a prosthesis including a first component and asecond component removably attachable to the first component. The methodalso includes the step of providing an instrument having a first memberoperably associated with the first component. The first member includesa first member relative motion feature and a body defining a generallycylindrical longitudinal opening therein. A second member is operablyassociated with the second component. The second member is operablyassociated with the first member for relative motion between the firstmember and the second member for assembly of the first component of theprosthesis to the second component. The instrument also includes anangular orientation feature cooperating with at least one of the firstmember and the second member for at least one of replicating andmeasuring the relative angular orientation of the first component withrespect to the second component. The method also includes the step ofassembling the first component to the second component. The method alsoincludes the step of connecting the first member of the tool to thefirst component. The method also includes the step of connecting thesecond member of the tool to the second component. The method alsoincludes the step of rotating the first member of the tool with respectto the second member of the tool to secure the first component to thesecond component.

According to a yet another embodiment of the present invention, there isprovided a method for providing joint arthroplasty. The method includesthe step of providing a trial prosthesis including a stem trial portionfor implantation at least partially into the femoral canal of a femurand a neck trial portion extending from the stem portion. The methodincludes the steps of positioning the stem trial portion in the femoralcanal and positioning the neck trial portion relative to the stem trialportion. The method includes the steps of securing the neck trialportion to the stem trial portion and trialing the trial prosthesis. Themethod includes the steps of attaching an instrument to the stem trialportion and the neck trial portion and measuring the relative positionof the stem trial portion to the neck trial portion. The method includesthe steps of providing a implant prosthesis including a stem implantportion for implantation at least partially into the femoral canal of afemur and a neck implant portion extending from the stem portion and ofproviding an instrument to secure the stem implant portion to the neckimplant portion while angularly orienting the stem implant portion tothe neck implant portion.

According to a yet another embodiment of the present invention, there isprovided an assembly tool for assembly of a first component of aprosthesis to a second component of the prosthesis for use in jointarthroplasty. The tool includes a first member in contact with the firstcomponent. The first member defines a first member longitudinal axisthereof. The tool also includes a second member connected to the secondcomponent. The second member defines a second member longitudinal axis.The first member longitudinal axis and the first member longitudinalaxis are coexistent. The first member and the second member are adaptedto provide for the assembly of the first component of the prosthesis tothe second component of the prosthesis. The second member is adapted toprovide relative motion of the second member with respect to the firstmember when the second member is rotated relative to the first memberabout the second member longitudinal axis for assembly of the firstcomponent of the prosthesis to the second component. The relative motionof the second member with respect to the first member is utilized toeffect the relative motion of the first component with respect to thesecond component to urge the second component into engagement with thefirst component. The first member has a first member relative motionfeature and the second member has a second member relative motionfeature. The first member relative motion feature and the second memberrelative motion feature cooperate with each other to provide therelative motion of the first member with respect to the second member.The first member relative motion feature and the second member relativemotion feature are adapted to reduce friction between each other.

According to a yet another embodiment of the present invention, there isprovided a kit for use in joint arthroplasty. The kit is for assembly ofa first component of a first prosthesis to a second component of thefirst prosthesis, as well as, for the assembly of a first component of asecond prosthesis to a second component of a second prosthesis. At leastone of the first component of the first prosthesis and the firstcomponent of the second prostheses and the second component of the firstprosthesis and the second component of the second prostheses has atleast one different dimension. The kit includes an assembly tool forassembly of the first component of the first prosthesis to the secondcomponent of the first prosthesis for use in joint arthroplasty. Theassembly tool includes a first member in contact with the firstcomponent. The first member defines a first member longitudinal axisthereof and a second member connected to the second component. Thesecond member defines a second member longitudinal axis thereof. Thefirst member longitudinal axis and the first member longitudinal axisare coexistent. The first member and the second member are adapted toprovide for the assembly of the first component of the prosthesis to thesecond component of the prosthesis. The second member is adapted toprovide relative motion of the second member with respect to the firstmember when the second member is rotated relative to the first memberabout the second member longitudinal axis for assembly of the firstcomponent of the prosthesis to the second component. The relative motionof the second member with respect to the first member is utilized toeffect the relative motion of the first component with respect to thesecond component to urge the second component into engagement with thefirst component. The first member includes a first member relativemotion feature and the second member includes a second member relativemotion feature. The first member relative motion feature and the secondmember relative motion feature cooperate with each other to provide therelative motion of the first member with respect to the second member.The kit also includes an adaptor removably connectable to the firstmember for permitting the assembly tool to connect the first componentof the second prosthesis to the second component of the secondprosthesis.

According to a further embodiment of the present invention, there isprovided a method for providing joint arthroplasty. The method includesthe step of providing a plurality of prostheses, each prosthesisincluding a first component and a second component removably attachableto the first component. At least one dimension of one of the first andsecond components of each prosthesis being different from that of theother prostheses. The method includes the step of providing a instrumenthaving a first member operably associated with the first component. Thefirst member includes a first member relative motion feature and a bodydefining a generally cylindrical longitudinal opening therein. Theinstrument also has a second member operably associated with the secondcomponent. The second member is operably associated with the firstmember for relative motion there between for assembly of the firstcomponent of the prosthesis to the second component. The instrumentincluding a plurality of adaptors. Each adaptor is suited for one of thedifferent prostheses. The method also includes the steps of selectingone of the plurality of prostheses and assembling the first component ofthe one prosthesis to the second component of the one prosthesis. Themethod also includes the steps of assembling the adaptor suited for theone prosthesis from the plurality of adaptors onto the instrument andconnecting the first member of the tool to the first component. Themethod also includes the steps of connecting the second member of thetool to the second component and rotating the first member of the toolwith respect to the second member of the tool to secure the firstcomponent to the second component.

The technical advantages of the present invention include the ability ofthe device to provide sufficient mechanical advantage to properly securethe components to form a secured joint. For example, according to oneaspect of the present invention, the first component is joined to thesecond component by a threaded connection. By changing the pitch of thethreadable connection, the mechanical advantage can be increased toprovide for a sufficient mechanical advantage.

For example, according to yet another aspect of the present invention,the first component and the second component have outwardly extendinghandles. The handles may have any suitable length and may be made longerto provide for additional mechanical advantage. Thus the presentinvention provides for sufficient mechanical advantage to properlysecure the prosthesis.

Another technical advantage of the present invention is the ability ofthe device to provide for optimum ergonomics. For example, according toone aspect of the present invention, the device is held and actuated byopposed extending handles, which may be easily gripped by the surgeonand rotated relative to each other to secure the joint. Thus, thepresent invention provides for simple optimum ergonomics.

Yet another technical advantage of the present invention includes theability of the device to provide for a measurement of forces in additionto the measurement of displacement. Due to frictional forces andadditional complications, displacements of the device do not alwaysdirectly linerally correspond to the forces that may be applied by thedevice. Therefore, there is an advantage to be able to measure the forceapplied by the device in addition to the displacement of the device. Forexample, according to another aspect of the present invention, a handleof the device may include a torque measuring feature, which may be usedto measure the torque applied to the device. Alternatively or inaddition thereto, the device may include a force washer or other forcetransducers along the axial body of the instrument in order that theforces applied may be directly measured.

Another technical advantage of the present invention includes theability of the device to limit the displacement of the instrument andtherefore to limit the force applied to the prosthesis. If excessiveforce is applied to the prosthesis it is possible to overtighten anddamage the component. For example, according to one aspect of thepresent invention, the displacement is physically limited by a helicalopening of limited length or by a limited amount of threaded engagementbetween the two components. It is also possible to provide for a devicewith a break-away torque limiter that limits the amount of torque thatthe device may apply. Thus, the present invention provides for anability to avoid over tightening of the prosthesis components.

Another technical advantage of the present invention is its simple andinexpensive design. For example, according to one aspect of the presentinvention, the device includes a cylindrical tube and a rod, whichslideably fits within the cylindrical tube. The tube and rod arethreadably connected so that when one component is rotated with respectto the other one, the one component moves axially relative to the otherone, providing for a simple, inexpensive way of utilizing a device todisassemble or assemble a component.

An additional advantage of the present invention includes the ability ofthe device to be utilized simply and easily to disconnect as well as toconnect the components of a modular prosthesis. For example, accordingto one aspect of the present invention, a component may be placed ontothe assembly device to provide for connecting features to disassemblethe device. Thus, the present invention provides for a simple and quickway of being utilized to disassemble as well as to assemble aprosthesis.

Another technical advantage of the present invention, includes theability of the device to control the orientation of the components whilethey are being connected. The device serves to maintain the orientationduring connection. For example, according to one aspect of the presentinvention, a first member is provided for operable association with theproximal body and a second member is operably associated with the distalstem. Further an angular orientation feature cooperates with the firstmember and the second member for containing the angular orientation ofthe first component with respect to the second component. The presentinvention provides for an ability to control the orientation of thecomponent while they are being secured to each other.

Another technical advantage of the present invention, is that angularorientation of the components of a modular prosthesis can be alignedangularly and secured to each other with a common device. For example,according to the present invention, an assembly tool is providedincluding a first member associated with the proximal body and thesecond member associated with a distal stem. An angular orientationfeature is provided which cooperates with the first member and thesecond member to orient the first component with respect to the secondcomponent. Thus the present invention provides for the ability to setthe angular orientation and secure the components of the modularprosthesis with a common device.

Yet another technical advantage of the present invention is that it canbe used to measure the angular orientation of the distal stem withrespect to the proximal body. For example, according to one aspect ofthe present invention the tool of the present invention includes anangular orientation feature, which cooperates with the first member andthe second member to measure the relative angular orientation of thefirst component with respect to the second component. Thus the presentinvention provides for the ability to measure the angular orientation ofthe distal stem with respect to the proximal body.

Yet another technical advantage of the present invention includes theability of the device to limit the force on the joint connection duringassembly. For example, according to one aspect of the present inventionthe first member or the second member of the assembly tool is adapted toprovide for limited predetermined amount of relative motion of the firstmember with respect to the second member along the second memberlongitudinal axis. Thus the present invention provides for the abilityto avoid over-tighting of the prosthesis components.

Yet another technical advantage of the present invention, includes theability of the device to monitor force or displacement at the connectingjoint of the modular prosthesis. For example, according to one aspect ofthe present invention the assembly tool of the present invention furtherincludes a displacement measuring device or a force measuring device formeasuring the displacement or force related to the relative motion ofthe second member with respect to the first member of the assembly tool.The displacement measuring device and the force measuring device may beutilized to limit the displacement of the force or by preventing theover-tighting of the prosthesis components. The displacement measuringdevice may be in the form of marks or indicia at the force measuringdevice may be in the form of a torque wrench.

Yet another technical advantage of the present invention includes theability of the device to permit the engagement of the distal stem to theproximal body while the proximal body is contacted to the assembly tool.For example, according to one aspect of the present invention theassembly tool further includes a fourth member which is cooperable withthe third member. The fourth member translates along the longitudinalaxis while the third member translates along the longitudinal axis. Thefourth member may be manually rotated about the fourth memberlongitudinal axis. Thus the fourth member serves to permit manualrotation of the second member to engage the second member to the distalstem to the proximal body manually. Thus the present invention providesfor the ability to assemble the tool to the distal stem while theproximal body is connected to the assembly tool.

Yet another technical advantage of the present invention includes theability of the device to accommodate a plurality of proximal bodies anddistal stem lengths. For example, according to one aspect of the presentinvention, a first member is axially adjustable along the first memberaxis to accommodate a different length of the first member and thesecond member. This variation in length between the first member and thesecond member provides for a fit to a plurality of proximal bodies anddistal stems. Thus, the present invention provides for the ability toaccommodate a plurality of proximal bodies and distal stems.

Yet another technical advantage of the present invention includes theability of the device to fit a plurality of proximal bodies and distalstem shape. For example, according to one aspect of the presentinvention the orientor which orients the first member is slideablyconnected to the first member. Thus the present invention provides foran ability for the proximal body to move axially with respect of thedistal stem providing for a fit of a plurality of different shapeproximal bodies and distal stems with a common assembly tool.

Yet another technical advantage of the present invention includes theability of the device to set the proximal body and distal stemorientation to a desired setting. For example, according to one aspectof the present invention, the assembly tool includes a first orientorthat is connected to the first component and a second orientor thatcooperates with the second component as well as a first timing featurethat cooperates with the first member and a second timing feature thatcooperates with the second member. The timing features and orientors canbe utilized to pre-set the proximal body and distal stem to a desiredsetting.

For example, according to one aspect of the present invention anassembly tool is provided including a first member in contact with thefirst component and a second member in contact with the second componentalong the first and second members longitudinal axis. Thus the presentinvention provides for a simple mechanical connection that provides fora small and compact instrument for assembling and disassembling amodular orthopedic implant.

The technical advantages of the present invention further include theability to accurately tighten a thread.

For example, according to another aspect of the present invention anassembly tool is provided that includes a first member for contact withthe first component and a second member connected to the secondcomponent where the second member is adapted to provide relative motionof the second member with respect to the first member. The first memberincludes a first member relative motion feature and the second memberincludes a second member relative motion feature where the relativemotion features are adapted to reduce friction. Further, the assemblytool includes a displacement measuring device or a force measuringdevice for measuring the displacement of force related to the relativemotion of the second member with respect to the first member. Thus, thepresent invention provides for an ability to accurately tighten thefirst component to the second component on a modular implant.

The technical advantages of the present invention further include theability to provide for a low friction device. The assembly tool includesa first member in contact with the first component and a second memberconnected to the second component. The first member and second memberinclude relative motion features that are adapted to reduce frictionbetween each other. Thus the present invention provides for a lowfriction device to secure a first component to a second component.

The technical advantages of the present invention further include theability to measure the clamping force of the first component against thesecond component of a prosthesis. For example, according to yet anotheraspect of the present invention an assembly tool is provided forassembling a first component to a second component of the prosthesis.The first member and the second member include relative motion features.The relative motion features are adapted to reduce friction between eachother. Further the assembly tool includes one of a displacementmeasuring device and a force measuring device for measuring thecorresponding displacement and force related to the relative motion ofthe first member with respect to the second member. Thus the presentinvention provides for measuring clamping force accurately by providingfor a force measuring device and providing for a low frictionconnection.

The technical advantages of the present invention further include theability to measure the torque utilized in connecting a first componentto a second component. For example, according to another aspect of thepresent invention an assembly tool is provided for connecting a firstcomponent to a second component of a prosthesis. The first memberincludes a first member relative motion feature and is in contact withthe first member. The second member includes a relative motion featureand the first relative motion feature and the second relative motionfeature provide the motion necessary to connect the first component tothe second component. The assembly tool also includes a torque measuringdevice for measuring the torque related to the relative motion of thesecond member with respect to the first member.

The technical advantages of the present invention further include theability to use the assembly tool with a variety of different prosthesis.For example and according to another aspect of the present invention akit for use in joint arthroplasty is provided. The kit includes anassembly tool including a first member and a second member whichcooperate with each other to advance the first component into engagingwith the second component. The kit also includes an adaptor removableconnected to the first member for permitting the assembly tool toconnect the first component to a second prosthesis having a size andshape different than the first prosthesis. Thus, the present inventionprovides for use with a variety of prostheses.

The technical advantages of the present invention further include theability to sterilize the assembly tool of the present invention. Forexample, according to yet another aspect of the present invention theassembly tool includes a first member and a second member that have twopiece construction. Each of the two pieces may be sterilized separatelyproviding for an assembly tool that is sterilizable.

Other technical advantages of the present invention will be readilyapparent to one skilled in the art from the following figures,descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view partially in cross-section of an embodiment of thepresent invention in the form of an assembly tool including a threadedconnection in operation with a prosthesis;

FIG. 2 is a perspective view of another embodiment of the presentinvention in the form of an assembly tool with a spiral cam and followermechanism shown in engagement with a prosthesis;

FIG. 3 is a cross section view of FIG. 2 along the line 3-3 in thedirection of the arrows;

FIG. 4 is a plan view of a two pieced modular hip stem than may beassembled with the assembly tool of FIG. 2;

FIG. 5 is an exploded plan view of the modular hip stem of FIG. 4;

FIG. 6 is a partial plan view of a proximal body of another embodimentof a two pieced modular hip stem than may be assembled with the assemblytool of FIG. 2 without the counter bore for the assembly nut as in thehip stem of FIG. 5;

FIG. 7 is a lateral view partially in cross section of the modular hipstem of FIG. 4;

FIG. 8 is a plan view of a three piece modular hip stem with a nut thatmay be assembled with the assembly tool of FIG. 2;

FIG. 9 is an exploded plan view of three piece modular hip stem of FIG.8;

FIG. 10 is a perspective view of the assembly tool of FIG. 2 installedonto the two-piece modular stem of FIG. 4;

FIG. 11 is a partial perspective view of the assembly tool of FIG. 2showing the inclined actuating area in greater detail;

FIG. 12 is a partial unwound view of the inclined actuating area of theassembly tool of FIG. 2 showing the inclined actuating area in greaterdetail;

FIG. 13 is a cross-sectional plan view of the assembly tool of FIG. 2showing the implant of FIG. 8 being disassembled;

FIG. 14 is a partial enlarged plan view of the assembly tool of FIG. 2showing the ramp actuation mechanism in greater detail;

FIG. 15 is a partial enlarged perspective view of the assembly tool ofFIG. 2 showing the ramp actuation mechanism in greater detail;

FIG. 16 is a partial perspective view of the assembly tool of FIG. 2showing spiral cam portion of the ramp actuation mechanism in greaterdetail;

FIG. 17 is a partial top view of the assembly tool of FIG. 2 partiallydisassembled, showing the spool of the ramp actuation mechanism ingreater detail;

FIG. 18 is a partial enlarged plan view of the assembly tool of FIG. 2showing the connector for cooperation with the actuation arm in greaterdetail;

FIG. 19 is a partial enlarged plan view partially in cross section ofthe assembly tool of FIG. 2 showing the connector of the actuation armin greater detail;

FIG. 20 is a plan view partially in cross section of the implant of FIG.4 showing the implant in engagement with the assembly tool of FIG. 2;

FIG. 21 is a plan view partially in cross section of the implant of FIG.8 showing the implant in engagement with the assembly tool of FIG. 2;

FIG. 22 is a partial enlarged view of the implant of FIG. 8 beingassembled with the assembly tool of FIG. 2;

FIG. 23 is a perspective view of the implant of FIG. 4 beingdisassembled with the assembly tool of FIG. 2;

FIG. 24 is a partial enlarged perspective view of the assembly tool ofFIG. 2 including the adaptor for use in disassembly;

FIG. 25 is a partial cross-sectional plan view of the assembly tool ofFIG. 2 showing the implant of FIG. 4 being disassembled and showing theremovable disassembly component in position on the assembly tool;

FIG. 26 is a partial top view of the assembly tool of FIG. 2 showing theremovable disassembly component in position on the assembly tool;

FIG. 27 is a partial enlarged plan view of the implant of FIG. 4 beingdisassembled with the assembly tool of FIG. 2;

FIG. 28 is a partial enlarged plan view of the implant of FIG. 8 beingdisassembled with the assembly tool of FIG. 2;

FIG. 29 is a plan view of another embodiment of the present invention inthe form of an assembly tool including a torque wrench for measuring thetorque applied to the modular implant;

FIG. 30 is a flow chart of a method of using the assembly tool of thepresent invention according to another embodiment of the presentinvention;

FIG. 31 is a perspective view of an assembly tool assembly tool withalignment feature according to another embodiment of the presentinvention;

FIG. 32 is an exploded plan view of an articulating reamer and a counterbored reamer for use to prepare a cavity in a long bone for theinsertion of an implant that may be assembled with the assembly tool ofthe present invention;

FIG. 33 is a perspective view of a proximal body trial in position onthe articulating reamer of FIG. 32 for use with an implant that may beassembled with the assembly tool of the present invention;

FIG. 34 is a perspective view of the proximal body trial/articulatingreamer assembly of FIG. 33 in cooperation with an alignment tool, theproximal body trial/articulating reamer assembly for use with an implantthat may be assembled with the assembly tool of the present invention;

FIG. 35 is a plan view of a proximal body/arcuate distal stem trialassembly for use with an implant that may be assembled with the assemblytool of the present invention;

FIG. 36 is a perspective view of the proximal body/arcuate distal stemtrial assembly of FIG. 34 in cooperation with the alignment tool of FIG.34, proximal body/arcuate distal stem trial assembly for use with animplant that may be assembled with the assembly tool of the presentinvention;

FIG. 37 is a perspective view of a proximal body trial/arcuate distalstem implant assembly in cooperation with the alignment tool of FIG. 34,the proximal body trial/arcuate distal stem implant assembly for usewith an implant that may be assembled with the assembly tool of thepresent invention;

FIG. 38 is a plan view of a proximal body implant/arcuate distal stemimplant assembly in cooperation with the assembly tool with alignmentfeature of FIG. 30;

FIG. 39 is a plan view partially in cross section of the assembly toolof FIG. 30 in cooperation with the implant assembly of FIG. 38;

FIG. 40 is aside view partially in cross section of the assembly tool ofFIG. 30 in cooperation with the implant assembly of FIG. 38;

FIG. 41 is a plan view of the assembly tool of FIG. 30 in cooperationwith the implant assembly of FIG. 38;

FIG. 42 is a partial plan view in cross section of the assembly tool ofFIG. 30 showing the torque input end in greater detail;

FIG. 43 is a cross sectional view of FIG. 42 along the line 43-43 in thedirections of the arrows;

FIG. 44 is a partial plan view in cross section of FIG. 37 showing aportion of the torque input end in greater detail;

FIG. 45 is a partial plan view in cross section of the assembly tool ofFIG. 30 showing the inner force transmitting portion in greater detail;

FIG. 46 is a partial top view of the assembly tool of FIG. 30 showingthe proximal body alignment portion in greater detail;

FIG. 47 is a partial end view of the proximal body alignment portion ofthe assembly tool of FIG. 30;

FIG. 48 is a plan view in cross section of the assembly tool of FIG. 30;

FIG. 49 is a partial top view of the assembly tool of FIG. 30 showingthe distal stem alignment groove and the proximal body alignment indiciain greater detail;

FIG. 50 is a partial plan view in cross section of the assembly tool ofFIG. 30 showing the upper portion in greater detail;

FIG. 50A is a cross sectional view of FIG. 50 along the line 50A-50A inthe directions of the arrows;

FIG. 51 is a partial plan view of the inner force transmitting portionof FIG. 45 in greater detail;

FIG. 52 is a plan view of a unitary reamer for use to prepare a cavityin a long bone for the insertion of an implant that may be assembledwith assembly tool of FIG. 37;

FIG. 53 is a plan view of a proximal body trial in position on theunitary reamer of FIG. 52 for use with an implant that may be assembledwith the assembly tool of FIG. 37;

FIG. 54 is a perspective view of the proximal body/unitary reamerassembly of FIG. 53 in cooperation with the alignment tool of FIG. 33,the proximal body/unitary reamer assembly for use with an implant thatmay be assembled with the assembly tool of FIG. 37;

FIG. 55 is a plan view of a proximal body/straight distal stem trialassembly for use with an implant that may be assembled with the assemblytool of FIG. 37;

FIG. 56 is a perspective view of the proximal body/straight distal stemtrial assembly of FIG. 55 in cooperation with the alignment tool of FIG.33, the proximal body/straight distal stem trial assembly for use withan implant that may be assembled with the assembly tool of FIG. 37;

FIG. 57 is a perspective view of a proximal neck trial/straight distalstem implant assembly in cooperation with the alignment tool of FIG. 33,the proximal body trial/arcuate distal stem implant assembly for usewith an implant that may be assembled with the assembly tool of FIG. 37;

FIG. 58 is a plan view of a proximal body implant/straight distal stemimplant assembly in cooperation with the assembly tool of FIG. 37;

FIG. 59 is a plan view of a proximal body trial with a proximal bodysleeve in position on the articulating reamer of FIG. 31 for use with animplant that may be assembled with the assembly tool of FIG. 37;

FIG. 60 is a perspective view of the proximal neck trial with a proximalbody sleeve/articulating reamer assembly of FIG. 59 in cooperation withthe alignment tool of FIG. 33, the proximal body trial with a proximalbody sleeve/articulating reamer assembly for use with an implant thatmay be assembled with the assembly tool of FIG. 37;

FIG. 61 is a plan view of a proximal body with a proximal bodysleeve/arcuate distal stem trial assembly for use with an implant thatmay be assembled with the assembly tool of FIG. 37;

FIG. 62 is a plan view of the proximal body with a proximal bodysleeve/arcuate distal stem trial assembly of FIG. 61 in cooperation withthe alignment tool of FIG. 33, the proximal body with a proximal bodysleeve/arcuate distal stem trial assembly for use with an implant thatmay be assembled with the assembly tool of FIG. 37;

FIG. 63 is a perspective view of a proximal body trial with a proximalbody sleeve/arcuate distal stem implant assembly in cooperation with thealignment tool of FIG. 33, the proximal body trial/arcuate distal stemimplant assembly for use with an implant that may be assembled with theassembly tool of FIG. 37;

FIG. 64 is a plan view of a proximal body implant with a proximal bodysleeve/arcuate distal stem implant assembly in cooperation with theassembly tool of FIG. 37;

FIG. 65 is a plan view of a proximal body trial with a proximal bodysleeve in position on the unitary reamer of FIG. 52 for use with animplant that may be assembled with the assembly tool of FIG. 37;

FIG. 66 is a perspective view of the proximal body with a proximal bodysleeve/unitary reamer assembly of FIG. 53 in cooperation with thealignment tool of FIG. 33, the proximal body with a proximal bodysleeve/straight reamer assembly for use with an implant that may beassembled with the assembly tool of FIG. 37;

FIG. 67 is a plan view of a proximal body with a proximal bodysleeve/straight distal stem trial assembly for use with an implant thatmay be assembled with the assembly tool of FIG. 37;

FIG. 68 is a perspective view of the proximal body with a proximal bodysleeve/straight distal stem trial assembly of FIG. 55 in cooperationwith the alignment tool of FIG. 33, the proximal body with a proximalbody sleeve/straight distal stem trial assembly for use with an implantthat may be assembled with the assembly tool of FIG. 37;

FIG. 69 is a perspective view of a proximal body trial with a proximalbody sleeve/straight distal stem implant assembly in cooperation withthe alignment tool of FIG. 33, the proximal body trial with a proximalbody sleeve/arcuate distal stem implant assembly for use with an implantthat may be assembled with the assembly tool of FIG. 37;

FIG. 70 is a plan view of a proximal body implant with a proximal bodysleeve/straight distal stem implant assembly in cooperation with theassembly tool of FIG. 37; and

FIG. 71 is a flow chart of a method of using the assembly tool of thepresent invention according to yet another embodiment of the presentinvention;

FIG. 72 is a flow chart of another method of using the assembly tool ofthe present invention according to yet another embodiment of the presentinvention;

FIG. 73 is a plan view of a proximal body implant/arcuate distal stemimplant assembly in cooperation with an assembly tool according to yetanother embodiment of the present invention showing an assembly toolwith a lever mechanism;

FIG. 73A is a partial plan view partially in cross section of FIG. 73showing the actuation members in greater detail;

FIG. 73B is a top view of FIG. 73 showing an alignment feature ingreater detail;

FIG. 73C is a partial plan view partially in cross section of FIG. 73showing the attachment to the distal stem of the prosthesis in greaterdetail;

FIG. 74 is a plan view of a proximal body implant/arcuate distal stemimplant assembly in cooperation with an assembly tool according to yetanother embodiment of the present invention showing an assembly toolinternally and externally threaded components;

FIG. 74A is a partial plan view partially in cross section of FIG. 74showing the cooperation of the actuation members in greater detail;

FIG. 74B is a top view of FIG. 74 showing an alignment feature ingreater detail;

FIG. 75 is a plan view of a proximal body implant/arcuate distal stemimplant assembly in cooperation with an assembly tool according to yetanother embodiment of the present invention showing an assembly toolwith a spiral engagement mechanism;

FIG. 75A is a partial plan view partially in cross section of FIG. 75showing the actuation members in greater detail;

FIG. 75B is a top view of FIG. 75 showing an alignment feature ingreater detail;

FIG. 76 is a perspective view of an assembly tool with alignment featurewith low friction actuation according to another embodiment of thepresent invention;

FIG. 77 is an exploded plan view of the assembly tool of FIG. 76;

FIG. 78 is a plan view partially in cross-section of the instrumenthousing of the assembly tool of FIG. 76;

FIG. 79 is a plan view of the shaft subassembly of the assembly tool ofFIG. 76 including implant connector and the draw thread subassemblywhich are connected by the coupling;

FIG. 80 is a cross sectional view of FIG. 79 through the line 80-80 inthe direction of the arrows;

FIG. 81 is an exploded plan view of the shaft subassembly of FIG. 79;

FIG. 82 is a plan view of the implant connector of the shaft subassemblyof FIG. 79;

FIG. 83 is a cross sectional view of FIG. 82 through the line 83-83 inthe direction of the arrows;

FIG. 84 is a plan view of the coupling of the shaft subassembly of FIG.79;

FIG. 85 is a cross sectional view of FIG. 84 through the line 85-85 inthe direction of the arrows;

FIG. 86 is a plan view of the draw thread subassembly of the shaftsubassembly of FIG. 79;

FIG. 87 is a cross sectional view of FIG. 86 through the line 87-87 inthe direction of the arrows;

FIG. 88 is a plan view of the hex drive of the assembly tool of FIG. 76;

FIG. 89 is a cross sectional view of FIG. 88 through the line 89-89 inthe direction of the arrows;

FIG. 90 is a plan view of the screw on adaptor of the assembly tool ofFIG. 76;

FIG. 91 is a cross sectional view of FIG. 90 through the line 91-91 inthe direction of the arrows;

FIG. 92 is a plan view of the handle post of the assembly tool of FIG.76;

FIG. 93 is a cross sectional view of FIG. 92 through the line 93-93 inthe direction of the arrows;

FIG. 94 is a plan view of the assembly tool of FIG. 76;

FIG. 95 is a cross sectional view of FIG. 94 through the line 95-95 inthe direction of the arrows;

FIG. 96 is an exploded plan view of a modular hip stem that may beassembled with the assembly tool of FIG. 76;

FIG. 97 is a partial plan view of the modular hip stem of FIG. 96;

FIG. 98 is a plan view of the modular hip stem of FIG. 96;

FIG. 99 is an end view of the modular hip stem of FIG. 96 implanted in afemur;

FIG. 100 is a plan view of the assembly tool of FIG. 76 in position onthe modular hip stem of FIG. 96;

FIG. 100A is a partial plan view, partially in cross section of FIG. 100showing the truncated threads in greater detail;

FIG. 101 is a flow chart of a method of using the assembly tool of thepresent invention according to another embodiment of the presentinvention;

FIG. 102 is a plan view of a first adaptor for use with the assemblytool of FIG. 76 assembled onto the assembly tool of FIG. 76;

FIG. 103 is a plan view of the first adaptor of FIG. 102;

FIG. 104 is a plan view of a second adaptor for use with the assemblytool of FIG. 76 assembled onto the assembly tool of FIG. 76;

FIG. 105 is a plan view of the second adaptor of FIG. 104;

FIG. 106 is a plan view of a third adaptor for use with the assemblytool of FIG. 76 assembled onto the assembly tool of FIG. 76;

FIG. 107 is a plan view of the third adaptor of FIG. 106;

FIG. 108 is a plan view of the assembly tool of FIG. 76;

FIG. 109 is a plan view, partially in cross section, of a two pieceassembly tool with alignment feature with low friction actuationaccording to another embodiment of the present invention;

FIG. 110 is a plan view, partially in cross section, of an assembly toolwith alignment feature with low friction actuation and length adjustmentaccording to another embodiment of the present invention; and

FIG. 111 is a plan view, partially in cross section, of an assembly toolwith alignment feature with low friction actuation, rotation/translationcapabilities, and length adjustment actuation according to anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention and the advantages thereof are bestunderstood by referring to the following descriptions and drawings,wherein like numerals are used for like and corresponding parts of thedrawings.

According to the present invention and referring now to FIG. 1, assemblytool 1 according to the present invention is shown. The assembly tool 1is used for assembly of a first component 2 of a prosthesis 4 to asecond component 6 of the prosthesis 4 for use in joint arthroplasty.The tool 1 includes a first member 8 operably associated with the secondcomponent 6. The first member 8 defines a first member longitudinal axis10 of the first member 8. The tool 1 also includes a second member 12operably associated with the second component 6. The second member 12defines a second member longitudinal axis 14 of the second member 12.The second member 12 is adapted to provide relative motion of the secondmember 12 with respect to the first member 8 when the second member 12is rotated relative to the first member 8 about the second memberlongitudinal axis 14.

The assembly tool 1 is suited for use with the prosthesis 4 when, forexample, the prosthesis 4 includes the first component 2 and the secondcomponent 6 which are engaged and disengaged by relative motions alongan axis. For example, the assembly tool 1 is suitable when theprosthesis 4 includes components, which are connected by a taperedconnection. For example, as shown in FIG. 1, the first component 2includes an internal taper 16 that mates with an external taper 18located on the second component 6.

As shown in FIG. 1, the first component 2 is engaged with the secondcomponent 6 when the first component 2 moves in the direction of arrow20 and/or when the second component 6 moves in the direction of arrow22. As shown in FIG. 1, the first member 8 is operably associated withthe first component 2 while the second member 12 is operably associatedwith the second component 6. To provide for the operable association ofthe components, it should be appreciated that the first member 8includes a first member operating feature 24 which is operablyassociated with a first component operating feature 26 of the firstcomponent 2. Similarly, the second member includes a second memberoperating feature 28 which cooperates with a second component operatingfeature 30 of the second component 6.

For simplicity, since the first member 8 and the first component 2 aremerely required to prevent motion of the two components toward eachother, the first member 8 and the first component 2 may be designed suchthat the first member operating feature 24 may be in the form of abottom and/or surface. Similarly, the first component operating feature26 may be in the form of a top surface of the first component 2.

The second member operating feature 28 and the second componentoperating feature 30 may be any features capable of urging the secondcomponent 6 upwardly in the direction of arrow 22. For example, forsimplicity, the second member operating feature 28 may be in the form ofinternal threads formed on the second component operating feature 26,which may mate with external threads 30 formed on the second component6.

The first member 8 and the second member 12 may have any shape orconfiguration capable of providing relative motion along first memberlongitudinal axis 10 and second member longitudinal axis 14. Forexample, and as shown in FIG. 1, the first member 8 may be in the formof a hollow component or tube. Similarly, the second member 12 may be inthe form of a rod or cylinder, which may slideably fit within the firstmember 8. As shown in FIG. 1, the first member 8 may include alongitudinal opening 32.

In order to move the second component 6 into engagement with the firstcomponent 2, it should be appreciated that the second member 12 mustmove in the direction of arrow 34 with respect to the first member 8. Inorder to provide relative motion between the second member 12 and thefirst member 8, as shown in FIG. 1, the second member 12 may include arod portion 36 having a cylindrical periphery 38 thereof. The firstmember 8 may, as shown in FIG. 1, include a cylindrical tubular portion40 that defines the opening 32 therein. The rod periphery 38 of thesecond member 12 defines an outside diameter OD which is matingly fittedwith dimension ID of the opening 32 of the tubular portion 40.

As shown in FIG. 1, the relative motion of the first member 8 withrespect to the second member 12 may be controlled by, for example, arelative motion feature 42. As shown in FIG. 1, the relative motionfeature 42 may be in the form of a threaded connection. The threadedconnection 42 may, for example, as shown in FIG. 1, include a firstmember relative motion feature 44 in the form, of for, example internalthreads. The internal threads 44 are formed on internal periphery 46 ofthe tubular portion 40 of the first member 8.

The relative motion feature 42 may also include a second member relativemotion feature 48. Second member relative motion feature 48 may be inthe form of, for example, external threads formed on rod portion 36 ofthe second member 12. The threads 44 and 48 cooperate to provide therelative motion of the second member 12 in the direction of arrow 34with respect to the first member 8. The threads 44 and 48 are matinglyengaged and have a pitch selected to provide for the desired mechanicaladvantage.

Preferably and as shown in FIG. 1, the amount of relative motion of thefirst member 8 with respect to the second member 12 is limited. Such alimited relative motion of the first member 8 with respect to the secondmember 12 correspondingly limits the motion of the first component withrespect to the second component 6 thus preventing over-tightening of theprosthesis 4. The motion of the first member 8 with respect to thesecond member 12 may be accomplished in any suitable fashion. Forexample, the external threads 48 may have a thread length LE which isslightly greater than the thread length LI of the internal threads 44 ofthe first member 8. Thus, the motion in the direction of arrows 34 and38 of the component 12 with respect to component 8 is limited by thedifference of the thread lengths LE and LI. It should be appreciatedthat the threads 44 and 46 may only limit the motion of the members 8and 12 if the major diameters of the threads 44 and 48 provideinterference with the first member 8 or the second member 12. It shouldbe appreciated that stops (not shown) may be utilized to limit therelative motion of the first member 8 with respect to the second member12. A cap 52 and a collar 54, both secured to first meter 8 and bothshown in phantom, may be utilized to limit the relative motion of thefirst member 8 with respect to the second member 12.

It should be appreciated that in order to move the second member 12 inthe direction of arrow 34 with respect to the first member 8, the secondmember 12 must be rotated in the direction of arrow 56 with respect tofirst member 8. This motion assembles the components 2 and 6. Similarly,it should be appreciated that in order for the second member 12 to movein the direction of arrow 39 with respect to the first member 8, thesecond member 12 must be rotated in the direction of arrow 60 withrespect to the first member 8. This motion disassembles the components 2and 6.

To provide the sufficient torque or mechanical advantage for rotatingthe second member 12 in the direction of arrow 56 and 60, it should beappreciated that the second member 12 may include a second member handle62 extending outwardly from the rod portion 36 of the second member 12.Similarly, it should be appreciated that to resist the force applied bythe second member handle 62, the first member 8 may similarly include afirst member handle 64 extending outwardly from the tubular portion 40of the first member 8. The handles 62 and 64 may have any suitable sizeand shape capable of receiving for example the hands of the surgeon oroperator of the assembly tool 1.

It should be appreciated that the assembly tool 1 may likewise beutilized to disassemble the first component 2 from the second component6. It should be appreciated that the assembly tool 1 may be adapted foruse for the disassembly of the first component 2 from the secondcomponent 6. It should be appreciated that one of the first member 8 andthe second member 12 may be associated with one of the first component 2and the second component 6 such that as the first member 8 is movedrelative to the second member 12, the first component 2 may bedisassembled from the second component 6. To accomplish this, one of thefirst member 8 and the second member 12 is operably associated with thefirst component 2 while the other of the first member 8 and the secondmember 12 is operably associated with the second component 6.

For example, and as shown in FIG. 1, the second member 12 may beoperably associated with the second component 6 by, for example,utilizing the second member cooperating feature 28 in the form ofinternal threads to cooperate with the second component operatingfeature 30 in the form of external threads. The first member 8 issimilarly operably associated with the first component 2.

In order that the second component 6 may be forced to move in thedirection of arrow 63 while the first component 2 is required to move inthe direction of arrow 65, the first component 2 must be restrained bythe first member 8. The first component 2 is held against the firstmember 8 by, for example, a third member 66.

The third member 66 cooperates with the first member 8 and the firstcomponent 2 to hold the two components against each other. The thirdmember 66 may cooperate with the first member 8 and the first component2 in any suitable fashion. For example, the first member 8 may include afirst member disassembly operating feature 68 which cooperates with thethird member 66. Similarly, the first component 2 may include a firstcomponent disassembly operating feature 70 which cooperates with thethird member 66.

The third member 66 may have any suitable design or shape and may, forexample, be in the form of first fork 72 and second fork 74. The forks72 and 74 may be urged together by, for example, springs 76. The firstfork 72 may include a first tine 78 which engages with the first memberdisassembly operating feature 68 in the form of, for example, a firstmember groove. Similarly, the first fork 72 may include a second tine 80for cooperation with the first component operating disassembly feature70 in the form of, for example, a second component groove. The secondfork 74 may include a first tine 82 for cooperation with the firstmember groove 68 as well as a second tine 84 for engagement with thesecond groove 70.

When utilizing the assembly tool 1 to assemble the first component 2 tothe second component 6 the third member 66 is not used. The assemblytool 1 is positioned with respect to the prosthesis 4 such that theinternal threads 28 of the second member 12 engage the external threads30 of the second component 6. The internal threads 28 and the externalthreads 30 are threaded into engagement with each other and the secondmember 12 is rotated with respect to the second component 6 until thebottom end surface 24 of the first member 8 is in contact with the topsurface 26 of the first component 2. At this point, the second memberhandle 62 is rotated in the direction of arrow 56 until the secondmember handle has come to the stop created by the relative motionfeature 42.

When utilizing the assembly tool 1 to disassemble the first component 2from the second component 6 the third member 66 is utilized and placedin position on the assembly tool 1. The forks 72 and 74 of the thirdmember 66 are placed in position in the first member grooves 68 and thefirst component grooves 70. The top surface 26 of the first component 2is thus in contact with the bottom end surface 24 of the first member 8.The second component 6 is then threadably engaged into the second member12. The second member handle 62 is then rotated in the direction ofarrow 60 until the relative motion feature 42 ends the movement of thesecond member handle 62 thereby disassembling the first component 2 fromthe second component 6.

Referring now to FIG. 2, another embodiment of the present invention isshown as assembly tool 100. The assembly tool 100 is utilized forassembling the first component 2 of the prosthesis 4 to the secondcomponent 6 of the prosthesis 4. The prosthesis 4 may be used, forexample, in joint arthroplasty. The tool 100 is similar to the tool 1 ofFIG. 1 and includes a first member 108 operably associated with thefirst component 2. The first member 108 defines a first memberlongitudinal axis 110 thereof. The assembly tool 100 further includes asecond member 112 which is operably associated with the second component6. The second member 112 defines a second member longitudinal axis 114thereof. The second member 112 is similar to second member 2 of theassembly tool 1 of FIG. 1. The second member 112 is adapted to providerelative motion of the second member 112 with respect to the firstmember 108 when the second member 112 is rotated relative to the firstmember 108 about the second member longitudinal axis 114.

The assembly tool 100 may be configured such that the relative motion ofthe second member 112 with respect to the first member 108 correspondsto the relative motion of the first component 2 with respect to thesecond component 6 to urge the second component 6 into engagement withthe first component 2.

Referring now to FIG. 3, the engagement of the assembly tool 100 withthe prosthesis 4 is shown in greater detail. As shown in FIG. 3, thesecond component 6 includes a second component operating feature in theform of external threads 30. The external threads 30 are matingly fittedto, for example, internal threads 128 formed on second member 112. Thefirst component 2 includes an operating feature in the form of, forexample, a top surface 26 which mates with bottom surface 124 of thefirst member 108 of the tool 100.

Since the first member 108 is in contact with the first component 2 asthe first component moves in the direction of arrow 122 relative to thefirst component 2, the second member 112, which threadably secured tothe second component 6 moves in the direction of arrow 134 relative tothe first member 108. Thus, the relative motion of the second member 112with respect to the first member 108 in the direction of arrow 134corresponds to the relative motion of the second component 6 withrespect to the first component 2 in the direction of arrow 122.

Referring now to FIG. 4, the prosthesis 4 is shown in greater detail.The prosthesis 4 as shown in FIG. 4 includes a taper connection 17. Asshown in FIG. 4, the taper connection consists of the external taper 18formed on the distal stem 6 that engages with internal taper 16 formedon the first component in the form of the proximal body 2.

It should be appreciated that the prosthesis for use with the assemblytool 1 or 100 of FIGS. 1 and 2, respectively, may include a proximalbody 2 and a distal stem 6 which have an interference connection thatis, for example, a interference connection of a cylindrical bore to acylindrical stem, as well as, a splined non-uniform cross-section stemto a splined or non-uniform cross-section opening. It should further beappreciated that proximal body and distal stem of the prosthesis 4 foruse with the assembly tool of the present invention may include a taperconnection in which the distal stem has an internal taper and theproximal body has an external taper.

Again referring to FIG. 4, the prosthesis 4 as shown may includeexternal threads 30 formed on the distal stem 6. The proximal body 2 mayinclude a neck 19 to which a head 21 may matingly be fitted. As anadditional precaution in assuring that the proximal body 2 remainssecured to the distal stem 6, the prosthesis 4 may further include a nut23 which threadably engages the external threads 30 of the distal stem6.

Referring now to FIG. 5, the prosthesis 4 is shown with the proximalbody 2 disassembled from the distal stem 6. The external taper 18 of thedistal stem 6 is defined by an included angle β1. In order that theproximal body 2 fits securely to the distal stem 6, the proximal body 2includes the internal taper 16 defined by included angle β2. The anglesβ1 and β2 may be generally the same. Alternatively the taper angle maybe divergent. The angles β1 and β2 should be chosen, such that the fitof the proximal body 2 to the distal stem 6 is secure.

Referring now to FIG. 6, an alternate prosthesis for use with theassembly device of the present invention is shown as prosthesis 204.Prosthesis 204 includes a proximal body 202 which does not include acounter bore. Prosthesis 204 may include a nut 223 which mates withouter face 226 that is not recessed. The nut 223 threadably engagesdistal stem 206.

Referring now to FIG. 7, an alternate embodiment of a prosthesis thatmay be utilized with the assembly tool 1 and 100 of FIGS. 1 and 2,respectively, is shown as prosthesis 304. The prosthesis 304 includes aproximal body 302 similar to the proximal body 2 of the prosthesis 4 ofFIG. 4. The prosthesis 304 also includes a distal stem 306 that isdifferent than the distal stem 6 of the prosthesis 4 of FIG. 4. Thedistal stem 306 is bent and has a proximal portion 307 having alongitudinal centerline 309 and a distal portion having a longitudinalcenterline 313. The centerlines 309 and 313 form angle β there between.The distal stem 306 may further include an elongated slot 329 extendingaxially from the end of the stem 306.

Referring now to FIGS. 8 and 9, another embodiment of a prosthesis foruse with the assembly tool of the present invention is shown asprosthesis 404. Prosthesis 404 is similar to the prosthesis 304 of FIG.7. Prosthesis 404 includes a proximal body 402 which is connected to adistal stem 406. The proximal body 402 includes a neck 419 to which ahead 421 may be positioned. The prosthesis 404 may further include a nut423 to assist in connecting the proximal body 402 to the distal stem406. The prosthesis 404 may further include an external sleeve 427 whichis fitted to the proximal body 402 by means of an internal taper 429which mates with an external taper 431 on the proximal body 402. Thestem 406 may be bent in a continuous arc.

Referring now to FIG. 10, the assembly tool 100 is shown in position onthe prosthesis 4. The first member 108 is in contact with the firstcomponent 2 and the second member 112 is threadably engaged to thesecond component 6. The assembly tool 100 is utilized to move the secondcomponent 6 in the direction of arrow 111 with respect to the firstcomponent 2. This relative motion is accomplished by moving the secondmember 112 in the direction of arrow 134 in relation to the first member108.

The relative motion of the first member 108 with respect to the secondmember 112 may be accomplished by, for example, a relative motionfeature 142. The relative motion feature 142 may include a first memberrelative location feature 144 in the form of slot 144 within which asecond member relative motion feature 148 in the form of, for example, apin is rollably restrained with the slot 144. The relative motionfeature 142 is utilized to move the second member 112 about the secondmember longitudinal axis 114 with respect to the first member 108.

Referring now to FIGS. 11, 12, 13, 14 and 15, the relative motionfeature 142 is shown in greater detail.

As shown in FIG. 16, the slot 144 extends from first centerline 151 tosecond centerline 153. The centerlines 151 and 153 represent the arcuateend portions of the slot 144 defined with a radius R′ equal to the slotwidth SW divided by two. The slot 144 is defined by a first assemblyload surface 155 and an opposed second disassembly load surface 157. Theload surfaces 155 and 157 are parallel to each other and spaced apart adistance equal to SW or the slot width SW.

A slot length angle θ defines the arcuate difference from first membercenterline 110 along slot radius R of the first member 108 between thefirst centerline 151 and the second centerline 153. The angle θpreferably selected to provide for the proper displacement of theassembly tool 100. The proper displacement of the assembly tool 100 maybe predetermined by calculating the desired locking force on the jointof the prosthesis 2.

Referring to FIG. 12, the assembly load surface 155 is inclined relativeto a surface perpendicular to the longitudinal axis 110 of the firstmember 108 at a ramp angle of α. The angle α, as well as, the radius R(see FIG. 16) affect the displacement of the assembly tool 100.

The dimensions of the relative motion feature 142 may be properlyselected by using the formula below:DI=(θ/360)×π×2R×Tan α

Where:

θ=the angular arm displacement in radians

R=the slot 144 radius from centerline 110 in inches

DI=the displacement in inches.

α=the ramp angle in degrees.

Referring now to FIG. 17, the assembly tool 100 may include a second pin149 opposed to the first pin 148 which matingly fits within a secondslot 145 opposed to the first slot 144. First and second pins 148 and149 are preferably diametrically opposed and the first slot 144 and thesecond slot 145 are likewise preferably diametrically opposed. Thesecond pin 149 and the second slot 145 serve to balance the forces andloads upon the assembly tool 100.

Referring again to FIG. 11, the assembly tool 100 may include anactuating arm 162 similar to arm 62 of tool 1 of FIG. 1 and arestraining arm 164 similar to arm 64 of tool 1 of FIG. 1. The actuatingarm 162 and the restraining arm 164 may be, for example, modular. Thearm 162, for example, may include an arm connecting base 159 and an armextension 161 removably connectable to the arm connecting base 159.

Referring now to FIG. 18, the arm connecting base 159 is shown ingreater detail. The arm connecting base 159 includes a base 163including a bayonet-type groove 165. A stem 167 may extend from the base163.

Referring now to FIG. 19, the arm extension 161 is shown in greaterdetail. The arm extension 161 may include a pair of pins 169 extendingtoward the opening 171 in the arm extension 161. The opening 171receives the base 163 and the stem 167 of the arm connecting base 159(see FIG. 18).

Referring again to FIG. 17, the construction of the pins 148 and 149 areshown in greater detail. To provide for rolling contact of the pins 148and 149 against the slots 144 and 145, respectively, the pins 148 and149 are preferably rotatably mounted on pin stems 173. The pin stems 173may be threadably connected to the second member 112. It should beappreciated that the pins 148 and 149 may be mounted to the pin stems173 by means of needle bearings (not shown).

Referring now to FIG. 20, the prosthesis 4 is shown in engagement withthe assembly tool 100. Surface 124 of the first member 108 of theassembly tool 100 is placed against top face 26 of the proximal body 2of the prosthesis 4. The internal threads 128 of the second member 112of the assembly tool 100 is threadably engaged with external threads 30of the stem 6 of the prosthesis 4. After the prosthesis 4 has beenassembled utilizing the assembly tool 100, nut 23 shown in phantom issecured to the external threads of the stem 6.

Referring now to FIGS. 21 and 22, the prosthesis 404 is shown inconnection with the assembly tool 100. Outer surface 124 of the firstmember 108 of the assembly tool 100 is placed against top surface 426 ofthe proximal body 402 of the prosthesis 404. The internal threads 128 ofthe second member 108 of the assembly tool 100 is threadably engagedwith external threads 430 of the distal stem 406. After the prosthesis404 has been assembled with the assembly tool 100, nut 423 shown inphantom is positioned on the external threads 430 of the distal stem406.

Referring again to FIG. 13, the assembly tool 100 is shown in greaterdetail. While the first member 108 and the second member 112 may be madeof a one-piece or unitary construction, it should be appreciated thatthe first member 108 and the second member 112 may be made of multiplecomponents or may be modular. For example, and referring to FIG. 13, thefirst member 108 may include a sleeve portion 140, having a lower sleeve186 as well as an upper sleeve 188.

The lower sleeve 186 may be connected to the upper sleeve 188 in anysuitable manner, for example, by welding, by press fit, or as shown inFIG. 13, by being threadably connected. The first member 108 may alsoinclude a third component in the form of the first member handle 164.The first member handle 164 may be removably connected to the uppersleeve 188 by, for example, a bayonet connection such as that describedin FIGS. 18 and 19 herein.

Similarly, the second member 112 may be made of a modular or multi-piececonstruction. For example, the second member 112 may include a rodportion 136 removably connected to a cap 152. The rod portion 136 may besecured to the cap 152 in any suitable fashion. For example, the cap 152may be welded to the rod portion 136, or be press fitted thereto.Alternatively, and as shown in FIG. 13, the rod portion 136 may bethreadably connected to the cap 152 by means of a screw 190 threadablysecured to the rod portion 136 and trapping the cap 152 there between.As shown in FIG. 13, the cap 152 and the rod portion 136 cooperate toform a spool 192 there between. The spool 192 includes a first retainingportion 194 extending from the rod portion 136 and a spaced-apart andparallel second restraining portion 196. A central portion 198 ispositioned between the first restraining portion 194 and the secondrestraining portion 196.

Continuing to refer to FIG. 13, the second member 112 of the assemblytool 100 further includes a ring 185 rotatably positioned about thecentral portion 198 of the rod portion 136. The pin 148 is retainablyconnected to the ring 185. The handle 162 is fixedly secured to the ring185 by, for example, a press fit or fitted connection similar to theconnection of FIGS. 18 and 19.

Referring now to FIGS. 23, 24, and 25, assembly tool 500 is shown foruse in disassembling the prosthesis 4. The assembly tool 500 is similarto the assembly tool 100 and in fact includes all the components of theassembly tool 100 plus a third member 566 for use in disassembling theprosthesis 4. The assembly tool 500 thus includes a first member 508identical to the first member 108 as well as a second member 512identical to the second member 112 of the assembly tool 100 (see FIG.13).

The assembly tool 500 includes an actuating arm 562 identical to theactuating arm 162 of the tool assembly 100. The assembly tool 500further includes a restraining arm 561 identical to the restraining arm162 of assembly tool 100, except that the arm extension 161 of therestraining arm 162 is moved from first arm stem 564 to second arm stem563. The assembly tool 500 includes a slot 544 identical to the slot 144of the assembly tool 100. Pin 548, identical to pin 148 of the assemblytool 100, slideably fits within the slot 548.

Referring now to FIG. 25, the third member 566 is shown in greaterdetail. The third member 566 includes a collar 576 which is slideablyfitted over the first member shoulder 568. First arm 572 and second arm574 are pivotally mounted to the collar 576 by pivot pins 579. The arms572 and 574 are urged in the direction of arrows 577 by springs 578positioned between the arms 572 and 574 and the collar 576. Screws 582are threadably secured to the arms 572 and 574 to limit the movement ofthe upper portion of the arms 572 and 574 toward the first member 508.First location pin 580 and second location pin 584 are positioned on thefirst arm 572 and the second arm 574, respectively, for engagement withholes 70 in the proximal body 2 of the prosthesis 4.

When disassembling the prosthesis for utilizing the assembly tool 500,the location pins 580 and 582 are engaged in the holes 70 of theproximal body 2 of the prosthesis 4. Internal threads 528 of the secondmember 508 are then threadably engaged into the external threads 30 ofthe distal stem 6 of the prosthesis 4. The second member 512 is thencontinually tightened until the second member 512 is finger tight to thedistal stem 6. The pins 580 and 584 are moved from the proximal body 2by first moving the arms 572 and 574 in the direction of arrows 581 bymeans of the operator's fingers. When in position the arms 572 and 574are released so that the pins 580 and 584 may be properly engaged in theholes 70 of the proximal body 2 of the prosthesis 4.

Referring now to FIG. 26, the collar 576 of the third member 566 isshown in position on the first member 508. The third member 566 isassembled to the first member 508 by moving the third member 566 in thedirection of arrow 575.

Referring now to FIG. 27, the assembly tool 500 is shown for use withthe prosthesis 4 to disassemble the proximal body 2 from the distal stem6. The pins 580 and 584 of the arms 572 and 574 of the third member 566are engaged in holes 70 of the proximal body 2 of the prosthesis 4. Theinternal threads 528 of the second member 512 are threadably engagedwith the external threads 30 of the distal stem 6. The second member 512is then moved downwardly in the direction of arrow 583, therebyseparating the distal stem 6 from the proximal body 2.

Referring now to FIG. 28, the assembly tool 500 is shown in engagementwith the prosthesis 404 to remove the distal stem 406 of the prosthesis404 from the proximal body 402. The pins 580 and 584 of the arms 572 and574 of the third member 566 are engaged in holes 470 of the proximalbody 402 of the prosthesis 404. The internal threads 528 of the secondmember 512 are threadably engaged with the external threads 430 of thedistal stem 406 of the prosthesis 404. The second member 512 is thenmoved in the direction of arrow 583 with respect to the proximal body402 of the prosthesis 404 thereby separating the distal stem 406 fromthe proximal body 402 of the stem 404.

Referring now to FIG. 29, another embodiment of the present invention isshown as assembly tool 600. Assembly tool 600 is similar to assemblytool 100 or assembly tool 500 of FIG. 2 and FIG. 24, respectively,except that articulating arm 662 of the assembly tool 600 is differentthan the articulating arm 562 of the assembly tool 500 in that thearticulating arm 662 includes a torque wrench 689 extending from the armstem 663. The torque wrench 689 serves to provide a reading of thetorque applied by the assembly tool 600. It should be appreciated thatthe torque wrench 689 may be of a type for recording or reading theapplied torque or may be a torque wrench which has a break away orclicking torque at a particular value. Such a torque limiting wrench mayprovide for an accurate torque to be applied by the assembly tool 600.It should be appreciated that a thrust washer or other force transducermay be positioned in the first member or the second member to monitorthe force asserted by the assembly tool.

Referring again to FIG. 10, another embodiment of the present inventionis shown as kit 700. Kit 700 includes the assembly tool 100 as well asthe prosthesis 4. The assembly tool 100 and the prosthesis 4 form a kit.The kit may be provided with the prosthesis 4 assembled or with theprosthesis 4 disassembled including both the proximal body 2 and thedistal stem 6.

Assembly tools 1, 100 and 500 as shown in FIGS. 1, 2 and 24respectively, may be made of any suitable material and may, for example,be made of a metal. If made of metal, preferably the assembly tool ismade of a sterilizable material. The assembly tools 100 and 500 may bemade of components of, for example, cobalt chromium alloy, stainlesssteel alloy, or a titanium alloy. Articulating surfaces of the assemblytool may be surface hardened by processes such as flame hardening.

Referring now to FIG. 30, another embodiment of the present invention isshown as surgical method 800. The method 800 includes a first step 802of providing a prosthesis including a first component and a secondcomponent removably attached to the first component. The surgicalprocedure 800 also includes a second step 804 of providing an instrumenthaving a first member and a second member rotatably movable with respectto the first member in a plane perpendicular with the first member, thefirst member cooperable with the second component and the second membercooperable with the second component.

The method 800 may further include a third step 806 of assembling thefirst component to the second component and a fourth step 808 ofconnecting the first member of the tool to the first component. Themethod 800 may further include a fifth step 810 of connecting the secondmember of the tool to the second component and a sixth step 812 ofrotating the first member of the tool with respect to the second memberof the tool to secure the second component to the first component.

According to the present invention and referring now to FIG. 31,assembly tool 900 is shown for assembly of a first component 814 of aprosthesis 816 to the second component 818 of the prosthesis 816 Theprosthesis 816 is for use in joint arthroplasty. According to thepresent invention, the tool 900 includes a first member 902 operablyassociated with the first component 814 and a second member 904 operablyassociated with the second component 818.

As shown in FIG. 31, the first member 902 and the second member 904 areadapted to provide for the assembly of first component 814 of theprosthesis 816 to the second component 818 of the prosthesis 816. Thesecond member 904 is operably associated to the second member 902 toprovide relative motion between the first member 902 and the secondmember 904 for assembly of the first component 814 to the secondcomponent 818.

As shown in FIG. 31, the assembly tool 900 further includes an angularorientor 906 that cooperates with the first member 902 or the secondmember 904 for either replicating or measuring the relative angularorientation of the first component 814 with respect to the secondcomponent 818.

Referring now to FIG. 32, articulating reamer 820 is shown for preparinga cavity 822 in a long bone 824. The cavity 822 provides for a positionin the long bone 824 for the insertion of, for example, prosthesis 816of FIG. 31. Articulating reamer 820 is particularly well suited for usein revision surgeries. In revision surgeries, the distal stem is placedmore distally than a primary prosthesis so that the distal stem mayengage undisturbed bone that has not previously supported a prosthesis.

The long bone 824, in particularly the femur for use in supporting thedistal stem of a hip prosthesis is typically curved or arcuate. The longbone 824 thus may have an arch or radius of curvature R defined by forexample, a radius of curvature R. The position of the arch or curvatureof long bone 824 is a reasonable indicator of the anatomy of thepatient. Thus the position of the curvature of the long bone 824 may bea relative indicator of the proper position of, for example the naturalfemoral head with respect of the position of the curvature of a longbone 824. The position of the curvature of the long bone 824 may thusprovide an indication of the proper alignment of the first component 814to the second component 818 of the prosthesis 816 of FIG. 31.

Referring again to FIG. 32, articulating reamer 820 includes a distalportion 826 that articulates with respect to the first or shaft portion828 of the reamer 820 about pivot point 830. A counter bone reamer 832may slideably fit over shaft portion 828 of the articulating reamer 820for reaming the proximal portion of the long bone 824 for receiving theprosthesis 816. The articulating reamer 820 may include a connector 834positioned on the proximal portion 828 of the articulating reamer 820.The articulating reamer 820 and the counter bore reamer 832 combine toform reamer assembly 812 and are well suited for use of long bones 824,which are arcuate. A more complete description of use of articulatingand counter bore reamers and their use with orthopaedic trials andimplants for hip revision surgeries can be more understood by referenceto U.S. patent application Ser. No. 10/606,304 filed Jun. 25, 2003entitled “NON-LINEAR REAMER FOR BONE PREPARATION AND ASSOCIATED METHOD”incorporated in its entirety by reference.

Referring now to FIG. 33, a modular body trial 836 is shown in positionon the articulating reamer 820. The modular body trial 836 and thearticulating reamer 820 may be used in revision hip arthroplasty withthe prosthesis 816 and the alignment tool 900 of the present inventionas shown in FIG. 31.

Referring again to FIG. 33, articulating reamer 820 remains in themedullary canal of the long bone 824 after the reaming operation hasbeen complete. The proximal body trial 836 is thus assembled into thearticulating reamer 820 while the reamer 820 is still in the canal ofthe long bone to form trial reamer assembly 837. This permits thetrialing of the prosthesis without the use of a modular trial and avoidsthe inaccuracy as well as the time involved in such an additional stepof removing the articulating reamer and inserting the distal end of theproximal body trial.

While the articulating reamer 820 is in location in the long bone, theproximal body trial 836 may be rotated in the direction of arrows 838along longitudinal axis 840 to properly position proximal trial body 836in the patient. For example, nut 842 may be loosened and the proximalbody trial 836 may be rotated in the direction of arrows 838 with teeth834 being used to control by finite angular movements of, the trial 836.For example if 24 teeth are positioned on the trial 836 each toothrepresents 15 degrees of movement. When the proximal body trial is inthe proper orientation, the nut 842 may be hand tightened to secure thetrial 836 into position.

Referring now to FIG. 34, once the proximal body trial 836 is in theproper position in the body, an alignment tool 846 may be utilized tomeasure the preferred angular orientation of the proximal body trial 836to the articulating reamer 820. The alignment tool 846 is shown ingreater detail in U.S. patent application Ser. No. 10/327,196 entitled“ALIGNMENT DEVICE FOR MODULAR IMPLANTS AND METHODS” incorporated here inits entirety by reference.

Referring now to FIG. 35, the proximal body trial 836 is shown assembledwith an arcuate distal trial assembly 848 to form the trial assembly850. The assembly 850 may be utilized instead of the body trialarticulating reamer assembly 837 of FIG. 33. The trial assembly 850 maybe used in addition to the proximal body trial articulating reamerassembly 837 as an additional step to verify the appropriateness of thetrial and corresponding prosthesis for the patient.

Referring now to FIG. 36, the assembly 850 is shown with the alignmenttool 846 in position on the proximal body trial 836. The alignment tool846 may be utilized to properly orient the proper body trial withrespect to arcuate distal stem trial 848 or be used to record therelative position of the proximal body trial 836 to the arcuate distalstem trial 848.

Referring now to FIG. 37, the alignment tool 846 is shown in position ontrial assembly 852. Trial implant assembly 852 includes proximal bodytrial 836 as well as arcuate distal stem implant or second component818. The alignment tool 846 is used to angularly orient proximal bodytrial 836 to arcuate distal stem 818 in a position similar to that ofthe trial assembly 850 or the proximal body trial arcuate reamerassembly 837 (see FIGS. 36 and 33, respectively). The arcuate distalstem trial 848 or the articulating reamer 820 may be removed from thecanal of the long bone and the arcuate distal stem implant 818 insertedin the long bone. The proximal body trial 836 is positioned with respectto the arcuate distal stem implant 818 by use of the alignment tool 846utilizing in the measurements or settings obtained from trial assembly850 or the reamer trial assembly 837.

Referring now to FIG. 38, the assembly tool with alignment feature 900of the present invention is shown in position on implant assembly orprosthesis 816.

Alignment information may be obtained from alignment tool 846 positionedon trial implant assembly 852 of FIG. 37, from trial assembly 850 ofFIG. 33 or from the proximal trial body articulating reamer assembly 837of FIG. 33. The alignment information may be used to determine theproper angular orientation of the arcuate distal stem implant withrespect to the proximal body implant 814 to provide for a properlyassembled implant assembly 816.

Referring now to FIG. 39, the assembly tool 900 is shown in greaterdetail. The assembly tool 900 may, as shown in FIG. 39, be configuredsuch that the first member 902 defines first member longitudinal 908.Similarly, the second member 904 may define a second member longitudinalaxis 910. The second member 904 may be adapted to provide relativemotion of the second member 904 with respect to the first member 902when the second member 904 is rotated relative to the first member 902about the second member longitudinal axis 910.

The relative motion of the second member 904 with respect to the firstmember 902 may be utilized to affect the relative motion of the proximalbody 814 or the first component with respect to the distal stem orsecond component 818 to urge the distal stem 818 into engagement withthe proximal body 814.

The assembly tool 900 may be adapted as shown in FIG. 39 to provide forthe first member 902 including a first member relative motion feature914. For example, the first member relative motion feature may be in theform of threads 914 formed on first member 902. Similarly, the secondmember 904 may include a second member relative motion feature 916. Thesecond member relative motion feature 916 may be in the form of, forexample, threads formed on second member 904. The first member relativemotion feature 914 and the second member relative motion feature 916cooperate with each other to provide the relative motion of the firstmember 902 with respect to the second member 904.

As shown in FIG. 39, the first member relative motion feature 914 or thesecond member relative motion feature 916 may include, as discussedabove, threads. As shown in FIG. 39, the first member 902 may include abody 918 defining a generally cylindrical opening 920 in the body 918.The second member 904 of assembly tool 900 may further include a portion922 of the second member 904, which is matingly fitted to transversewithin the cylindrical longitudinal opening 920 of the first member 902.The portion 922 may be in the form of, for example, a translatingmember.

As shown in FIG. 39, the assembly tool 900 may further include acooperating member 924 for cooperating with the second component ordistal stem 818. The cooperating member 924 cooperates with the angularorientation feature 906 to replicate and/or measure the angularorientation of the first component 814 with respect to the secondcomponent or distal stem 818. The cooperating member 924 may have anysuitable size and shape and may for example, be in the form of acylindrical rod extending longitudinally through assembly tool 900. Thecooperating member 924 may include the second member relative motionfeature or tang 912.

As shown in FIG. 39, the assembly tool 900 may be configured such thatthe first component or proximal body 814 of the implant assembly 816includes an internal taper 854. Similarly, the distal stem or secondcomponent 818 of the implant assembly 816 may include an external taper856. The second component 818 may further an external thread 858extending from the external taper 856. The second member 904 may includean internal thread 926 for making an engagement with external threads858 of the second component 818.

As shown in FIG. 39, the assembly tool 900 may be configured such as thefirst member longitudinal axis 908 and the second member longitudinalaxis 910 are coincident.

While the angular orientation feature 906 of the assembly tool 900 mayhave any suitable size, shape, and configuration, the angularorientation feature 906 may for example, include first orientor 928connected to the first member 902. The first orientor 928 cooperateswith the first component or proximal body 814 of the implant assembly816. The first component 814 includes a first timing feature 860. Thefirst orientor 928 is operably associated with the first timing feature860. For example, and is shown in FIG. 39 the first orientor may includea pair of pins 930, which mate with openings 862 located on the firstcomponent 814.

The angular orientation feature 906 may further include a secondorientor in the form of, for example tang 912. The tang 912 is operablyassociated with the second member 904 for cooperation with the distalstem or second component 818 of the implant assembly 816. The secondcomponent 818 includes a second timing feature 864 in the form of, forexample, a slot. The second orientor or tang 912 is operably associatedwith the second timing feature 864, for example, the slot.

Referring now to FIG. 40, the assembly tool 900 may further include adevice for preventing or controlling over-tighting or securing of thefirst component 814 to the second component 818 of the implant assembly816.

The assembly tool 900 may include a displacement measuring device 930 ora force measuring device 932, or both. The displacement measuring device930 may be utilized for measuring the displacement of the firstcomponent 814 relative to the second component 818. Similarly, the forcemeasuring device 932 may be utilized for the measuring of the forcerelated to the relative motion of the first component 814 with respectto the second component 818.

The displacement measuring device 930 may be for example, in the form ofindicia 930 including a first mark 934 on for example, first member 902and a second mark 936 moveable with, for example, second component 818.The distance between the first mark 934 and the second mark 936 may berepresentative of the displacement of the first component 814 withrespect to the second component 818.

Force measuring device 932 may be in the form of, for example thrustwasher 932. It should be appreciated that additional force measuringdevices in the form of for example, a strain gage or similar devices maybe utilized. Alternatively, the force measuring device 932 may be in theform of, for example, torque wrench 938. The torque wrench 938 may be ahand or power tool. The torque wrench 938 may include a feature (notshown) to limit torque such as a clutch or power tool control.

Referring now to FIG. 41, the assembly tool 900 may be configured suchthat the first member 902 and or the second 904 include a handle 942extending outwardly from the first member 902 or the second member 904.For example, and as is shown in FIG. 41, the handle 942 extendsoutwardly from handle stem 940, which extends outwardly from firstmember 902 of the assembly tool 900. The handle 942 is utilized toassist in holding and stabilizing the assembly tool 900 and to provideresistance to the assembly tool 900 as it is utilized to remove or jointhe implant assembly 816.

Referring now to FIGS. 42 and 45, the assembly tool 900 may beconfigured such that the first member 902 defines a central cavity 920in the first member 902. Further the assembly tool 900 may be configuredsuch that first member 902 also includes a translating member ortranslating portion 922 cooperable with the first member 902. Thetranslating member 922 may be fitted at least partially in the centralcavity or opening 920. The translating member 922 may define atranslating member longitudinal axis 944. The translating member 922 maybe adapted as shown in FIG. 42, to translate along the translatingmember longitudinal axis 944 when the second member 904 is rotated.

Referring now to FIGS. 46 and 47, the first orientor 928 of the angularorientation feature 906 is shown in greater detail. While the firstorientor 928 may have any suitable shape or configuration capable oforienting first component 814, the first orientor 928 for example, mayinclude a pair of spaced apart arms 946, which rotate about pivot pins948. Engagement pins 930 are matingly fitted into the openings 862formed in the proximal body 814 of the implant assembly 816. The firstorientor 928, as shown in FIG. 47, is thus pivotally connected to thefirst member 902. The pins 948, shown in FIG. 47, are connected to firstorientor body 950.

Referring now to FIG. 48, the body 950 of the first orientor 928 isslideably fitted to body 918 of the assembly tool 900. The ability ofthe first orientor 928 to slideably and pivotally be movable to respectto the assembly tool 900 permits the pins 930 to engage the proximalbody 814 of the implant 816 in many different positions permitting avariety of proximal body configurations to be compatible with assemblytool 900.

While the first member 902 and the second member 904 may each have anintegral or one-piece construction, it should be appreciated the firstmember 902 and the second member 904 may be made of two or morecomponents. For example and referring now to FIG. 48, the assembly tool900 may include a modular first member 902 and a modular or multi-piecesecond member 904.

For example and is shown in FIG. 48, the first member 902 may includethe body 918. Body cap 952 may be for example, threadably secured toproximal end 954 of the body 918 of the first member 902.

As shown in FIG. 48, a turnbuckle 956 is threadably secured to the body918 and an orientation sleeve 958 is threadably secured to the turnbuckle 956. The orientor housing 950 slideably fits over the orientationsleeve 958 and axially extending key 960 positioned between the orientorhousing 950 and the orientation sleeve 958 serves to prohibit rotationof the orientor housing 950 about the orientation sleeve 958. The turnbuckle 956 permits the first member 902 to be adjustable along the firstmember longitudinal axis 908.

The first member 902 may first include inner spool 962. The inner spool962 is oriented angularly with the body 918 and the remaining portion offirst member 902. The inner spool 962 is connected to the body 918 bybeing slideably connected and angularly oriented by means of keyway 964to translating member 922. The translating member 922 is angularlyconnected to the body 918 by means of tabs 966 extending from thetranslating member 922, which slideably cooperate with recesses 968formed in body 918 of the first member 902. (See FIG. 58)

Continuing to refer to FIG. 48, the second member 904 may also bemodular or be made of more than one component. For example and is shownin FIG. 48, the second member 904 includes a nut 970. The nut 970 mayinclude external flats 972 (see FIG. 43) and may for example, and isshown in FIG. 43 include six flats 972 or be hexagonal. A drive shaft974 may be operably connected to 970.

For example and referring again to FIG. 43, the drive shaft 974 mayinclude flats 976, which cooperate with the drive nut 970. A pin 978 maybe utilized to secure the drive shaft 974 to the nut 970.

Referring again to FIG. 44, the second member 904 further includes thetranslating member 922. The translating member 922 is slideablypositioned within the opening 920 formed in the body 918 of the firstmember 902. The translating member 922 is threadably connected to thedrive shaft 974 of the second member 904.

For example and is shown FIG. 44, the translating member 922 includeinternal threads 914, which matingly engage with external threads 916formed on the drive shaft 974. As the drive shaft 974 rotates with thenut 970 of the second member 904, the translating member 922 translatesalong second member longitudinal axis 910. Tabs 966 formed ontranslating member 922 cooperate with recesses 968 formed on the body918 of the first member 902 (see FIG. 58).

Referring again to FIG. 45, the second member 904 further includes atranslator adaptor 980, which may secured to the translating member 922by any suitable means. For example and is shown in FIG. 45, thetranslator adaptor 980 is secured to the translating member 922 by meansof a threaded engagement.

The second member 904 further includes a thumb wheel sleeve 982 which,as shown in FIG. 45, may be pivotally secured to the adaptor 980 bybearings 984. A proximal body adaptor stem 986 may be secured to thumbwheel sleeve 972 by any suitable method. For example and is shown inFIG. 45, the proximal body adaptor stem 986 may be threadably secured tothe thumb wheel sleeve 982.

The drive shaft 974 of the second member 904 may be rotatably secured tothe housing 918 of the first member 902 by means of second bearings 988sandwiching the drive shaft 974 between body cap 952 and body 918 of thefirst member 902.

Referring now to FIG. 49, the angular orientation feature of theassembly tool 900 further includes indicia 990 on the first member 902or the second member 904. For example and is shown in FIG. 49, indicia990 may include spool indicia 992 formed on inner spool 962 of the firstmember 902. The spool indicia 992 may include marks 944 extending fromfirst member longitudinal axis 908. Spool indicia 992 may furtherinclude letters or numerals 996 adjacent radial marks 994 formed on theinner spool 962. The indicia 990 as shown in FIG. 49 may further includea radial mark 998 formed on central alignment stem 999.

Referring now to FIG. 50, the assembly 900 may be configured as is shownin FIG. 50 with the second member 904 further including a rotatablemember, for example thumb wheel sleeve 982. The thumb wheel sleeve 982defines a thumb wheel longitudinal axis 983 of the thumb wheel sleeve982. The wheel sleeve 982 is cooperable with the translating member 922.The rotatable member or wheel sleeve 982 is adapted to translate alongthe rotatable longitudinal axis 983 with the translating member 922 whenthe translating member 922 translates along the translating memberlongitudinal axis 923. The rotatable member 982 is adapted to bemanually rotated about the rotatable member longitudinal axis 983 toadvance the proximal body adaptor stem 986 in the direction of arrow925.

Referring now to FIG. 39-51, the assembly tool 900 is shown in use withthe implant assembly 916. The assembly tool 900 may, as shown FIG.39-51, include numerous components which are assembled together. Theassembly tool 900 may be made of any suitable, durable material ormaterials. For example, the assembly tool 900 may be made of a durableplastic, a metal, or a composite material.

Preferably the assembly tool 900 is designed to be sterilizable bycommercially available sterilization techniques, for example, byauto-claving. The assembly tool 900 may be made a variation of metals.The assembly tool 900 may for example, by made of a metal, such as acobalt chromium alloy, a stainless steel alloy, or a titanium alloy. Theassembly tool 900 may use for assembly and disassembly 916. It should beappreciated that the assembly tool 900 may be used to secure and releaseproximal body 814 from the distal stem 818 of the implant assembly 816.

Alignment tool 846 (see FIG. 34) may be utilized to measure or set theangle orientation of the first component 814 with respect to the secondcomponent 818. Alternatively, a measurement may be made with, forexample, the alignment tool 846 of FIG. 34, to determine the angularorientation preferred from example, trialing of the trial assembly 850of FIG. 35 or the proximal body trial and articulating reamers assembly837 of FIG. 34 to determine the appropriate angular orientation of thefirst component 814 to second component 818. The angular orientationdesired may be measured by utilizing the alignment tool 848 of FIG. 36and the assembly tool 900 may be utilized to set or align the angularorientation of the component 814 to the second component 818.

The assembly tool 900 is assembled onto the prosthesis 816 by advancingthe assembly 900 along the second member longitudinal axis 908 of theassembly 900. As shown in FIGS. 40, 46, and 47 the angular orientationfeature 906 is adjustable to assist the assembly tool into engagementwith the first component 814 of the implant 816.

For example and is shown in FIGS. 46 and 47, the first orientor 928 ofthe angular orientation feature 906 includes a spring 903, which is usedto move the arms 904 to second position or assembly position 905 as isshown in phantom. In the assembly position 905, the pins 930 areextending apart sufficiently to permit the pins 930 to clear sidewalls863 of the proximal body 814 of the prosthesis 816. After the firstorientor 928 passes along the sidewalls 863 of the proximal body 814.The proximal body adaptor stem 986 of the second member 904 engages thesecond component or distal stem 818 (see FIG. 48).

Referring again to FIG. 39, internal threads 926 located on end 907 ofthe proximal body adaptor stem 986 are next threadably engaged withexternal threads 858 located on the distal stem 818 of the implant 816.The internal threads 926 are engaged with the external threads 858 byrotating the proximal body adaptor stem 986 by using for example, thumband index finger to rotate the thumb wheel sleeve 982.

Referring to FIG. 40, the thumbs wheel sleeve 982 may be reached forrotation by placing one's thumb and index finger against the thumb wheelsleeve 982 through first window 911 and second window 913 formed in thebody 918 of the first member 902 of the assembly tool 900.

Referring again to FIG. 39, the proximal body adaptor stem 986 isrotated until the internal threads 926 of the proximal body adaptor stem986 are in complete engagement with the external threads 858 on thedistal stem 818. At this point the assembly tool 900 is advanceddownward in the direction of the arrow 919 along the first memberlongitudinal axis 908 until the lower end 915 of orientor cap 917 of theorientor housing 950 contacts the proximal face 861 of the proximal body814 of the prosthesis 816.

Once the assembly 900 is seated against the proximal face 861 of theproximal body 814 and now referring FIGS. 46 and 47 thumb screw 921 isthreadably secured to the orientor housing 950 of the first orientor928. The thumb screw 921 is rotated to advance thumb screw stem 923against the arms 946 of the first orientor 928. As the stem 923 isadvanced the arms 946 move from assembly position 905 as shown inphantom to the operating position 925 as shown in solid. Pins 930 arefitted within the openings 862 in the proximal body 814 of the implantassembly 816.

It should be appreciated that the orientor housing 950 may be slideablymoved along the orientor sleeve 958 so that the pins 930 will engage inthe openings 862. When the arms 946 of the first orientor 928 of theassembly tool 900 are in the operating position 925, the angularorientation of the proximal body 814 to the distal stem 818 may beverified.

For example and referring now to FIG. 49, the radial mark 998 on thecentral aligning stem 999 corresponds to the angular position of thedistal stem 818 while the spool indicia 992 on the inner spool 962 ofthe first member 902 indicate the angular position of the proximal body814 of the prosthesis 816. For example and is shown in FIG. 49, theradial mark 998 of the central alignment stem 999 shows that thealignment stem 999 or distal stem 818 are in position at a negative to10 degree right position relative to the first member or proximal body814.

Once the assembly tool 900 is properly positioned on the prosthesis asshown in FIGS. 39-41 and is described heretofore, the torque wrench 938is positioned on nut 970 and is rotated to secure the distal stem 818into the proximal body 814.

Referring now to FIGS. 50, 50A, and 51, as the nut 970 is rotated, thedrive shaft 974 which is secured to the nut 970 also rotates with thenut 970. As the drive shaft 970 rotates, the external threads 916 on thedrive shaft 974 engage with internal threads 914 formed on thetranslating member 922. Since the translating member 922 includes tabs966, which mate with the recesses 968 (see FIG. 50A), the translatingmember 922 may not rotate about axis 983. Thus, as the drive shaft 974rotates, the translating member 922 translates downwardly into thedirection of arrow 925.

The translating member 922 is fixably secured to the translating adaptor980. The translating adaptor 980 is positioned between the thumb wheelsleeve 982 and the proximal body adaptor stem 986. Thus as thetranslator adaptor 980 moves downwardly in the direction of arrow 925,the thumb wheel sleeve 982 and the proximal body adaptor stem 986likewise move downwardly in the direction of arrow 925.

Referring now to FIG. 48, since the proximal body adaptor sleeve 986 isthreadably engaged to the distal stem 818, the distal stem 818 movesupwardly into the direction of arrow 931 as the nut 970 and drive shaft974 are rotated.

As shown in FIG. 40, the torque wrench 938 is used to limit the forceplaced upon the nut 970 and correspondingly on the distal body adaptorstem 986, the torque wrench 938 eventually limits the force placed onthe distal stem 818 of the prosthesis 816.

Referring now to FIG. 52, an unitary, fixed or straight reamer 1020 isshown for use to prepare the cavity 822 of the long bone 824 forinsertion of the implant that may be assembled with the assembly tool ofFIG. 31. The fixed reamer 1020 includes, as is shown in FIG. 52, areamer cutting portion 1026 which engages bone in the cavity 822 of thelong bone or femur 824. The fixed reamer 1020 also includes a reamerstem 1028 extending from the reamer cutting portion 1026. A reamerdriver 1032 engages the reamer stem 1028 and is used for connection to adriving device 1034.

Referring now to FIG. 53, a proximal body trial fixed reamer assembly1037 is shown. The assembly 1037 includes the proximal body trial 836 ofFIG. 33 installed in position on the fixed reamer 1020 of FIG. 52 foruse with an implant the may be assembled with the assembly tool of FIG.31.

The angular orientation of the proximal body trial 836 may be variedaround longitudinal axis 1040 in the directions of arrows 1038. A nut842 may be loosened on the proximal body trial 836 and the teeth 844 ontrial 836 may be used to indicate a finite angular motion about thelongitudinal axis 1040. For example, if the trial 836 has 24 teeth onthe proximal body trial 836, each tooth may represent a motion of forexample, 15 degrees.

Once the proper alignment is determined by trialing of the proximal body836 with regard to the straight or fixed reamer 1020, referring now toFIG. 54, the next step is performed. The alignment tool 846 of FIG. 34may be positioned on the proximal body trial 836 of FIG. 33 to determineand record the proper alignment of the distal stem or fixed reamer 1020with respect to the proximal body trial 836.

Referring now to FIG. 55, a trial assembly 1050 is shown for use with animplant that may be assembled with assembly tool of FIG. 31. The trialassembly 1050 may include a straight distal trial 1048 secured to theproximal body trial 836 of FIG. 33.

Referring now to FIG. 56, the trial assembly 1050 of FIG. 55 is shownwith the alignment tool 846 of FIG. 34 positioned on the proximal bodytrial 836. It should be appreciated that the use of the proximal body836 may be eliminated and the trialing may be made solely from reamersand distal implants.

Referring now to FIG. 57, a trial implant assembly 1052 is shown for usewith an implant that may be assembled with the assembly tool of thepresent invention. For example and is shown in FIG. 57, the trialimplant assembly 1052 includes a straight distal stem implant 1018 towhich proximal body trial 836 of FIG. 33 may be assembled. The alignmenttool 846 of FIG. 34 may be utilized to determine the angle orientationof the proximal body trial 836 with respect to the straight distalimplant 1018.

Referring now to FIG. 58 implant assembly 1016 is shown for use withassembly tool with alignment feature 900 of FIG. 31. The implantassembly 1016 includes the straight distal stem implant 1018 of FIG. 57secured to proximal body 814 of FIG. 38. The angular orientor 928 of theassembly tool 900 is secured to proximal body 814 of the implantassembly 1016. The torque wrench 938 is secured to nut 970.

Referring to FIG. 59, yet another trial reamer assembly is shown astrial assembly 1137. The trial reamer assembly 1137 of FIG. 59 includesthe articulating reamer 820 of FIG. 32 to which, a proximal body trial1136 is attached. The proximal body trial 1136 includes a neck portion1139 including an external taper 1141 to which internal taper 1143 of aproximal sleeve trial 1135 is matingly fitted forming trial assembly1137. The proximal sleeve trial 1135 is used to provide additionalproximal support for the trial 1136. The angular orientation of the bodyportion 1139 of the assembly 1137 may be angularly adjusted alonglongitudinal axis 1140 by rotating the neck portion 1139 aboutlongitudinal axis 1140 in direction of the arrows 1138. A nut 1142 maybe rotated to loosen the teeth 1144 of the body portion 1138. As theteeth 1144 are allowed to disengage, one tooth spacing, the proximalbody trial 1136 may rotate relative to the articulating reamer 840.

Referring now to FIG. 60, the proximal body trial articulating reamerassembly 1137 is shown with alignment tool 846 of FIG. 34 in position onproximal body trial 1136. Alignment tool 846 is utilized to measure theangular orientation of the proximal body trial 1146 with respect to thearticulating reamer 820.

Referring now to FIGS. 61 and 62, the trial assembly 1160 is shown. Thetrial assembly 1150 include the arcuate distal trial 848 of FIG. 35 withthe proximal body trial 1136 and proximal sleeve trial 1135 in positionon the distal trial 848. It should be appreciated that the use of distaltrial 848 may be avoided.

Referring now to FIG. 63, implant assembly 1152 is shown for use with animplant that may be tightened by the assembly tool of the presentinvention. The trial implant assembly 1152 includes the arcuate distalimplant 818 of FIG. 37 with the proximal body trial 1136 and theproximal sleeve trial 1135 in position on the arcuate distal implant818. The alignment tool 846 of FIG. 34 may be utilized to measure theangular orientation of the proximal body trial with respect to thearcuate distal implant 818.

Referring now to FIG. 64, the assembly alignment tool 900 of the presentinvention is shown in position on implant assembly 1116. The implantassembly 1116 includes the arcuate distal stem implant 818 of FIG. 37 towhich proximal body implant 1114 is secured. A proximal body sleeve 1115is positioned between the proximal body 1114 and the arcuate distal stem818. The assembly/alignment tool 900 may be used to align and tighten aswell as to disassemble the proximal body implant to the distal stemimplant 818.

Referring now to FIG. 65, yet another proximal body trial reamerassembly is shown which may be utilized with an implant that may betightened with an assembly alignment tool of the present invention. Forexample and is shown in FIG. 65, a proximal body trial/straight reamerassembly 1237 is shown. The assembly 1237 includes the straight reamer1020 of FIG. 52 to which proximal body trial 1136 and proximal sleevetrial 1135 of FIG. 59 is secured. The proximal body trial 1136 may berotated with respect to the straight reamer 1020 about longitudinal axis1140 in the direction of arrows 1238.

Referring now to FIG. 66, the proximal body/trial straight reamerassembly 1237 of FIG. 65 is shown with alignment tool 846 of FIG. 34 inposition on the proximal body trial 1136 of the trial straight reamerassembly 1237.

Referring now to FIG. 67, a trial implant assembly 1252 is shown for usewith an implant assembly that may be assembled with the assemblyalignment tool of the present invention. The trial implant assembly 1252includes the straight distal implant 1118 of FIG. 57 to which proximalbody trial 1136 of FIG. 59 is secured. Proximal sleeve 1135 of FIG. 59is positioned between the straight distal implant 1118 and the proximalbody trial 1136. Alignment tool 846 of FIG. 34 may be utilized toangular orient or to measure the angle of orientation of the proximalbody trial 1136 to the straight distal implant 1118.

Referring now to FIG. 68, trial assembly 1250 is shown for use with animplant that may be assembled using the assembly and alignment tool ofthe present invention. The trial assembly 1250 includes the straightdistal trial 1048 of FIG. 55 to which body trial 1136 of FIG. 59 issecure. Proximal sleeve trial 1135 of FIG. 59 may be positioned betweenthe proximal body trial 1136 and the straight distal stem trial 1148.

Referring now to FIG. 69, alignment tool 846 of FIG. 34 is shown inposition on trial assembly 1250 of FIG. 68. The trial assembly 1250includes a proximal body trial 1136 to which the straight distal stemtrial 1048 is positioned. It should be appreciated that the distal trial1048 may be avoided.

Referring now to FIG. 70, implant assembly 1216 is shown for use inassembly/alignment tool 900 of FIG. 31.

The implant assembly includes the implant straight distal stem 1018 ofFIG. 58 to which implant proximal body 1114 of FIG. 64 is attached. Theimplant proximal sleeve 1115 of FIG. 64 is positioned between theproximal body 1114 and the implant straight distal stem 1118.

Referring now to FIG. 71, a method 1300 for performing orthopaedicsurgery is shown. The method includes a first step 1310 of providing aprosthesis including a first component and a second component removablyattached to the first component. The method includes a second step 1312of providing an instrument that has a first member operably associatedwith the first component. The first member includes a first memberrelative motion feature and a body defining a generally cylindricallongitudinal opening in the body.

The instrument also includes a second member operably associated withthe second component. The second member is operably associated with thefirst member for relative motion between the first member and secondmember for assembly of the first component of the prosthesis to thesecond component.

The instrument further includes an angular orientation featurecooperating with the first member and the second member for replicatingand or measuring the relative angular orientation of the first componentwith respect to the second component.

The method 1300 further includes a third step 1314 of assembling thefirst component to the second component. The method 1300 furtherincludes a fourth step 1316 of connecting the first member of the toolto the first component and a fifth step 1318 of connecting the secondmember of the tool to the second component. The method 1300 furtherincludes a sixth step 1320 of rotating the first member of the tool withrespect to the second member of the tool to secure the first componentto the second component.

According to the present invention and referring now to FIG. 72, anotherembodiment of the present invention is shown as a method of performingorthopaedic surgery 1400. The method 1400 includes a first step 1410 ofproviding a trial prosthesis including a stem trial portion forimplantation at least partially into the femoral canal of a femur and aneck trial portion extending from the stem portion. The method 1400further includes a second step 1412 of positioning the stem trialportion in the femoral canal.

The method 1400 further includes a third step 1414 of positioning theneck trial portion relative to the stem trial portion and a fourth step1416 of securing the neck trial portion to the stem trial portion. Themethod 1400 also includes a fifth step 1418 of trialing the trialprosthesis and a sixth step 1420 of attaching an instrument to the trialstem portion and a neck trial portion.

The method 1400 further includes a seventh step 1422 of measuring therelative position of the stem trial portion to the neck trial portion.The method 1400 further includes an eighth step 1424 of providing animplant prosthesis including a stem implant portion for implantation atleast partially into the femoral canal of femur and a neck implantportion extending from the stem portion.

The method 1400 further includes a ninth step 1426 of providing aninstrument to secure the stem implant portion to the neck implantportion while angularly orienting the stem implant portion to the neckimplant portion.

Referring now to FIG. 73, another embodiment of the present invention isshown as assembly tool 1500. Assembly tool 1500 is used for assemblingthe first component, for example, proximal body 814 of prosthesis 816 toa second component for example, distal stem 818 of the prosthesis 816for use in joint arthroplasty. The tool 1500 includes a first member1502 in the form of, for example, a body having a cylindrical opening.

First member 1502 is operably associated with the proximal body 814 ofthe prosthesis 816. For example and is shown in FIG. 73A, a firstorientor 1528 similar to the first orientor 928 of FIG. 48 of assemblytool 900 may be utilized to orient the proximal body 814 to the firstmember 1502 of the assembly tool 1500.

The assembly tool 1500 may further include a second member 1504. Thesecond member 1504 is operably associated with the second component ordistal stem 818. For example and is shown in FIG. 73, the second member1504 is in the form of a tube or sleeve and is slideably fitted withinthe first member 1502. The second member 1504 may include internalthreads 1526, which engage with external threads 858 of the distal stem818. The first member 1502 and the second member 1504 are adapted toprovide for the assembly of the proximal body 814 of the prosthesis 816to the distal stem 818 of the prosthesis 816.

The second member 1504 is operably associated with the first member 1502for relative motion between the first member 1502 and the second member1504 for assembly of the first component or proximal body 814 to thedistal stem or the second component 818.

The assembly tool 1500 further includes an angle orientation feature1506. The angular orientation feature 1506 cooperates with the firstmember 1502 and the second member 1504 for replicating and/or measuringof the relative angular orientation of the proximal body 814 withrespect to the distal stem 818.

Referring now to FIG. 73C, the assembly tool 1500 as shown in FIG. 73includes a central rod or central alignment stem 1599 which is slideablyfitted within the second member 1504. The central alignment stem 1599includes a second orientor or tang 1512, which engages with slot 864formed in the distal stem 818 of the prosthesis 816.

To align the proximal body 814 to the distal stem 818, the proximal body814 is aligned with the first member 1502 through the first orientor1528 while the distal stem 818 is angularly oriented with respect to thealignment stem 1599 by the tang or second orientor 1512.

Referring now to FIG. 73B, radial mark 1598 located on the centralalignment stem 1599 is used with marks 1592 formed on second member 1504to combine as indicia 1590 to provide a visual representation of theangular orientation between the distal stem 818 and the proximal body814.

Referring again to FIG. 73, to provide the axial motion of the secondmember 1504 in the direction of arrow 1513, a lever mechanism 1515 isattached to the first member 1502 and to the second member 1504. Forexample and is shown in FIG. 73, the lever mechanism 1515 includes afirst pivoting position 1517 pivotally positioning the lever mechanism1515 with respect to first member 1502. The lever mechanism 1515 furtherincludes a second pivoting position 1519 to connect the level mechanism1515 to a link 1521. The link 1521 is pivotally connected to the secondmember 1504 at a third pivoting position 1523.

Continuing to refer to FIG. 73, as lever arm 1525 of leveling mechanism1515 is rotated in the direction of arrow 1527, the link 1521 urgessecond member 1504 in the direction of arrow 1513 to engage the distalstem 818 to the proximal body 814.

Referring now to FIG. 74, another embodiment of the present invention isshown as assembly tool 1600. Assembly tool 1600 is used to assemblefirst component for example, proximal body 814 of prosthesis 816 tosecond component 818 for example, distal stem 818 of the prosthesis 816for use in joint arthroplasty. The assembly tool 1600 includes a firstmember 1602. The first member 1602 is operably associated with theproximal body or first component 816.

For example and is shown in FIG. 74, the first member 1602 is in theform of a cylindrical sleeve. An angular orientation feature 1606includes as shown in FIG. 74, a first orientor 1628. The first orientor1628 is similar to the orientor 928 of FIGS. 31-50. The first orientor1628 physically angularly locks the proximal body 814 to the firstmember 1602.

The assembly tool 1600 further includes a second member 1604 that isoperably associated with the second component 816. For example and isshown in FIG. 74, the second member 1604 is in the form of a tube, whichis slideably fitted within the first member or sleeve 1602. The secondmember 1604 includes internal threads 1626, which engage with externalthreads 858 located on the distal stem 818. The first member 1602 andthe second member 1604 are adapted to provide for the assembly of theproximal body 814 to the distal stem 818. The second member 1604 isoperably associated with the first member 1602 for relative motionwithin the first member 1602 and the second member 1604. For example andis shown in FIG. 74, the second member 1604 is slideably fitted withinthe first member 1602.

As earlier discussed, the assembly tool 1600 further includes theangular orientation feature 1606. The first member 1602 defines a firstmember longitudinal axis 1608 and the second member 1604 defines asecond member longitudinal axis 1610. The second member 1604 is adaptedto provide relative motion of the second member 1604 with respect to thefirst member 1602 when the second member 1604 is rotated relative to thefirst member 1602 about the second longitudinal axis 1610. The relativemotion of the second member 1604 with respect to the first member 1602is utilized to affect the relative motion of the proximal body 814 withrespect to the distal stem 818 to urge distal stem 818 into theengagement of the proximal body 814.

For example and is shown in FIGS. 74 and 74A, the first member 1602includes a first member relative motion feature in the form of, forexample, internal threads 1614. The second member 1604 includes a secondmember relative motion feature in the form of, for example, externalthreads 1616. The internal threads 1614 and the external threads 1616cooperate with each other to provide the relative motion of the secondmember 1604 with respect to the first member 1602.

For example and is shown in FIG. 74, as nut 1670 located on the end ofsecond member 1604 is rotated, the second member 1604 is rotatedrelative to the first member 1602. Because of the internal threads 1614and external threads 1614, the second member 1614 advances in thedirection of arrow 1613.

As shown in FIGS. 74 and 74A, the internal threads 1614 on the firstmember 1602 extend a length L1, which is greater than the distance L2that external threads 1616 of the second member 1604 extend. Thedifference between the length L2 and L1 represents L Δ or amount ofmotion along longitudinal axis 1608 that the second member 1604 may moverelative to the first member 1602.

Continuing to refer to FIG. 74, the angular orientation feature 1606includes first orientor 1628 as well as second orientor 1612. The firstmember 1602 defines a first member longitudinal axis 1608 while thesecond member 1604 defines second longitudinal axis 1610. The firstmember 1602 is rotatively secured to the proximal body or the firstcomponent 814 by the first orientor 1628. The second angular orientor ortang 1612 is rotatively keyed the second component or distal stem 818 byslot 864 in the distal stem 818. The relative angular position of theproximal body 814 with respect to the distal stem 818 about longitudinalaxis 1608 corresponds to the angular orientation of the first angularorientor 1628 with respect to the second angular orientor or tang 1612.

Referring now to FIG. 75, another embodiment of the present invention isshown as assembly tool 1700. The assembly tool includes a first member1702 in the form of a hollow cylindrical body. The assembly tool 1700further includes a second member 1704 in the form of a hollow tube. Thetube 1704 is rotatively fitted within the first member or body 1702. Anorientation stem 1799 is slideably fitted within the second member ortube 1704.

A spiral cam mechanism 1713 is utilized to move the second member 1704along longitudinal axis 1708 of assembly tool 1700. Spiral cam mechanism1713 includes a spiral cam shaped opening 1715 formed in first member orbody 1702. The opening 1715 exposes second member or tube 1704. Afollower 1717 extends outwardly from the second member 1704 through camshaped opening 1715 in first member 1702. The follower 1717 is attachedto the actuator 1738 and is positioned in the opening 1715 for matinglyengagement with the body 1702. As the actuator 1738 is rotated in thedirection of arrows 1719 the second member 1704 is caused to rotate toadvance the second member 1704 in the direction of arrows 1719 along thelongitudinal axis 1708 of the assembly tool 1700.

Referring now to FIG. 75A, a first orientor actuator 1728 similar to thefirst orientor 928 of FIGS. 31-51 is secured to the first member 1702. Astem 1799 slideably fits within the second member or tube 1704 andincludes a second orientor or tang 1716, which mates with slot 864 inthe proximal body 814 of the prosthesis 816.

Referring now to FIG. 75, indicia 1790 utilized to orient the proximalbody 814 to the distal stem of the prosthesis 816. The stem 1799includes a radial mark 1798, which is aligned with body indicia 1792located on first member or body 1702 of the assembly tool 1700. The bodyindicia 1792 and the radial mark 1798 are utilized to determine andestablish the angular orientation of the proximal body 812 to the distalstem 818.

Referring again to FIG. 31, another embodiment of the present inventionis shown as kit 1000. The kit 1000 includes an implant 816 as well asthe assembly tool 900.

According to the present invention and referring now to FIG. 109, anassembly tool 1800 according to the present invention is shown. Theassembly tool 1800 is utilized for assembling a first component 1802 ofa prosthesis 1804 to a second component 1806 of the prosthesis 1804 foruse in joint arthroplasty. The assembly tool 1800 includes a firstmember 1808 in contact with the first component 1802. The first member1808 defines a first member longitudinal axis 1810. The tool 1800further includes a second member 1812 connected to the second component1806. The second member 1812 defines a second member longitudinal axis1814. The first member longitudinal axis 1810 and the second memberlongitudinal axis 1814 are co-existent or are lying in the same axis.

The first member 1808 and the second member 1812 are adapted to providefor the assembly of the first component 1802 of the prosthesis 1804 tothe second component 1806 of the prosthesis 1804. The second member 1812is adapted to provide relative motion of the second member 1812 withrespect to the first member 1808 when the second member 1812 is rotatedrelative to the first member 1808 about the second member longitudinalaxis 1814 for assembly of the first component 1802 of the prosthesis1804 to the second component 1806 of the prosthesis 1804.

The relative motion of the second member 1812 with respect to the firstmember 1808 urges the second component 1806 into engagement with thefirst component 1802.

The first member 1808 includes a first member relative motion feature1816. The second member 1812 includes a second member relative motionfeature 1818. The first member relative motion feature 1816 and thesecond member relative motion feature 1818 cooperate with each other toprovide the relative motion of the first member 1808 with respect to thesecond member 1812. The first member relative motion feature 1816 andthe second member relative motion feature 1818 are adapted to reducefriction between each other.

The relative motion features 1816 and 1818 may be any features capableof reducing the friction between the relative motion features 1816 and1818. For example, the relative motion features may be in the form ofthreads where the adaptation for reducing friction is in the form of acoating. The coating may be in the form of polytetrafloraethylene orPTFE. Alternatively, the friction reducing feature may be in the form ofa lubrication in the form of for example, a lubricant that is compatiblewith the human body and adaptable in surgical procedures. Such alubricant is Stella® Lubricant.

Alternatively, the friction reduction feature for the relative motionfeatures may be in the form of the nature of relative motion featureitself. For example, the relative motion features may be in the form ofa ball screw where each of the members 1808 and 1812 may include concavehelical threads with balls being placed between the helical concavethreads.

The assembly tool 1800 of FIG. 109 includes the first member 1808 whichhas a body 1822 defining a generally longitudinal opening 1822 extendingalong first member longitudinal axis 1810. The second member 1812includes a portion 1824 of the second member 1812 which is matinglyfitted to traverse along the cylindrical longitudinal opening 1822 ofthe first member 1808.

The assembly tool 1800 of FIG. 109 is adapted for use with the firstcomponent 1802 that includes an internal taper 1828 and the secondcomponent that includes an external taper 1830. The second component1806 also includes an external thread 1832 extending from the externaltaper 1830. The second member 1812 defines a truncated internal thread1834 for mating engagement with the truncated internal thread 1834 ofthe second component 1806.

According to the present invention and referring now to FIG. 110, yetanother embodiment of the present invention is shown as assembly tool1900. The assembly tool 1900 of FIG. 110 is similar to the assembly tool1800 of FIG. 109, except that the assembly 1900 of FIG. 110 includes asecond member 1912 that is some what different from the second member1812 of the assembly 1800 if FIG. 109.

For example and as shown in FIG. 110, the second member 1912 includesexternal threads 1916 which mate with internal threads 1918 formed onfirst member 1908. The first member 1908 defines a first member centerline 1910 which is co-existent with a second member center line 1914.

The second member 1912 is modular member or has a two piececonstruction. For example and as shown in FIG. 110, the second member1912 includes a shaft portion 1936.

Referring now to FIG. 111, yet another embodiment of the presentinvention is shown as assembly tool 2000. The assembly tool 2000includes a first member 2008 which defines a central cavity 2024. Atranslating portion 2038 cooperates with the first member 2008 and isfitted at least partially in the central cavity 2024 of the first member2008. The translating portion 2038 is adapted to translate but notrotate along second member longitudinal axis 2014 when second member2012 is rotated. The translating portion 2038 may be able to translatebut not rotate by providing a protrusion 2040 extending from thetranslation portion 2038 which mates with a groove 2042 formed in firstmember 2008. The translating portion 2038 is connected to rotatingportion 2044 of the second member 2012. The rotating portion 2044 isthreadably engaged to the first member 2008 and defines a pocket 2046for receiving a portion of the translating portion 2038 such that therotating portion 2044 advances the translating portion 2038 alonglongitudinal axis 2014 of the second member 2012.

According to the present invention and referring now to FIG. 100, yetanother embodiment of the present invention is shown as assembly tool2100. The assembly tool 2100 is used for assembling a prosthesis 2104.The prosthesis 2104 includes a first component 2102 for which theassembly tool 2100 is used to assemble the first component 2102 to thesecond component 2106 to form the prosthesis 2104. The prosthesis 2104is used in joint arthroplasty.

As shown in FIG. 100, the prosthesis 2104 is in the form of a hipfemoral stem assembly. The hip femoral stem assembly 2104 includes asecond component 2106 in the form of a distal stem implant and a firstcomponent 2102 in the form of a proximal femoral stem component. Theassembly tool 2110 includes a first member 2108 which is in contact withthe first component 2102. The first member 2108 defines a first memberlongitudinal axis 2110.

It should be appreciated that the first member 2108 may have a unitaryor one piece construction. However, to provide for proper sterilizationby traditional sterilization methods such as by Autoclaving®, the firstmember 2108 may have a modular construction. The modular constructionprovides for easy assembly and disassembly. For example, a modular firstmember 2108 may, for example, have threads to mate with threadedportions of other components. For example, and as shown is FIG. 100, thefirst member 2108 includes a body 2122 from which handle 2120 isthreadably connected. An end cap 2146 is also threadably connected tothe body 2122. An adaptor 2148 may be removably connected by, forexample, a circular helical spring 2150 to the end cap 2146.

The assembly tool 2100 further includes a second member 2112 which is incontact with second component 2106. The second component 2106 may, as isshown in FIG. 100, be in the form of a distal stem component which mateswith the proximal body 2102 to form the prosthesis 2104. The secondmember 2112 defines a second member longitudinal axis 2114. The secondmember longitudinal axis 2114 and the first member longitudinal axis2110 are, as is shown in FIG. 100, co-existent or co-linear.

As is shown in FIG. 100, the first member 2108 and the second member2112 are adapted to provide for the assembly of the first component 2102of the prosthesis 2104 to the second component 2106 of the prosthesis2104. Further, the second member 2112 is adapted to provide relativemotion of the second member 2112 with respect to the first member 2108when the second member 2112 is rotated relative to the first member 2108about the second member longitudinal axis 2114 for assembly of the firstcomponent 2102 of the prosthesis 2104 to the second component 2106. Therelative motion of the second member 2112 with respect to the firstmember 2108 is utilized to affect the relative motion of the firstcomponent 2102 with respect to the second component 2106 toward thesecond component 2106 into engagement with the first component 2102.

To urge the first component 2102 into engagement with the secondcomponent 2106, the first member 2108 includes a first member relativemotion feature 2116 and the second member 2112 includes a second memberrelative motion feature 2118. The first member relative motion feature2116 and the second member relative motion feature 2118 cooperate witheach other to provide the relative motion of the first member 2108 withrespect to the second member 2112.

The first member relative motion feature 2116 and the second memberrelative motion feature 2118 may have any suitable configuration. Thefirst member relative motion feature may as shown in FIG. 100, be in theform of internal threads. Similarly the second member relative motionfeature 2118 may be in the form of external threads which mate with theinternal threads 2116 of the first member.

According to the present invention, the first member relative motionfeature or internal threads 2116 and the second member relative motionfeature 2118 in the form of external thread are adapted to reducefriction between the internal threads 2116 and the external threads2118. While the reduction of friction between the internal threads 2116and the external threads 2118 may be accomplished in many ways, forexample, by providing the threads in the form of helical grooves withballs positioned between the helical grooves to form a ball-screwthreaded arrangement, or by providing coatings to the surfaces of thethreads 2116 and 2118, or by coating the threads 2116 and 2118 with alubricant, the applicants have found that, for example, the use oftruncated threads is particularly well suited for the assembly tool 2100of the present invention.

Referring now to FIG. 100A, the relative motion feature for the secondmember 2118 and the first member relative motion feature 2116 is shownin greater detail. The first member 2108 includes the body 2122 ontowhich internal threads 2116 are formed. The internal threads 2116 matewith external threads 2118 formed on shaft 2136 of the second member2112. The external threads 2118 include crest 2150 and roots 2152 which,as shown in FIG. 100A, are truncated. Similarly, internal threads 2116include crest 2154 and roots 2156 which, likewise, are truncated.

While any truncated thread may accomplish the reduced friction of thepresent invention, it should be appreciated that Acme threads areparticularly well suited for the low friction relative motion of thepresent invention. It should be appreciated that coatings may be appliedto the threads 2118 and 2116 in the form of, for example, a non-sticksurface, for example polytetrafluoroethylene (PTFE). Also, the surfacefinish or roughness of the external threads 2118 and the internalthreads 2116 may be optimized to reduce the friction between thethreads. Further, a lubricant, for example Stella® Lube, may be utilizedto reduce the friction between the external threads 2118 and theinternal threads 2116.

Referring again to FIG. 100, the first member 2108 and the second member2112 may include a feature for providing mechanical advantage to assistin the relative motion of the first member 2108 with respect to thesecond member 2112. For example, the first member 2108 may include ahandle 2120 extending outwardly from the first member 2108. While thehandle 2120 may be an integral handle, preferably, to simplifymanufacture and to assist in cleaning by autoclave or othersterilization techniques, the handle 2120 may be modular including ahandle post 2158 which is threadably engaged with body 2122 of the firstmember 2108. A handle extension 2160 may be connected by, for example, abayonet connection to the handle post 2158.

The assembly tool 2100 may include the first member 2108 which has abody 2122 which defines central longitudinal opening 2124 extendingalong longitudinal center line 2110 of the first member 2108. Further,the second member 2112 may include a portion 2126 of the second member2112 that matingly fits with the first member 2108 to traverse along thecylindrical longitudinal opening 2122 of the first member 2108. As shownin FIG. 100, the central longitudinal opening 2122 in the first member2108 includes the internal threads 2116 along which the external threads2118 of the shaft 2136 of the second member 2112 traverse.

Referring still to FIG. 100, the assembly tool 2100 includes the firstmember 2108 which has the central longitudinal cavity or opening 2122positioned in the body 2122 of the first member 2108. The second member2112, as shown in FIG. 100, includes a translating portion 2137 as wellas a rotating portion 2138. The rotating portion 2138 both rotates inthe direction of arrows 2162 as well as translates along second memberlongitudinal axis 2114 in the direction of arrow 2164. The translatingportion 2137 merely translates but does not rotate. The translatingportion 2138 moves merely along arrow 2164. The value of having arotating portion 2138 in the second member 2112 is that the translatingportion 2138 is engaged with the second component 2106 to draw alonglongitudinal axis 2110 and 2114 of the first member and second memberrespectively such that external taper 2130 of the second component mayoptimally engage with internal taper 2128 of first component 2102.

While the second member 2112 may have a one piece construction,preferably, and as shown in FIG. 100, the second member 2112 has amodular construction such that components of the second member 2112 maybe easily disassembled for cleaning or sterilization by commonsterilization methods such as by Autoclaving®. For example and as shownin FIG. 100, the second member 2112 may include a rotating portion 2144that represents separate components from translating portion 2138 of thesecond member 2112.

The rotating portion 2144 of the second member 2112 may in itself bemodular. For example and as is shown in FIG. 100, the rotating portion2144 may include a shaft 2136 for threadably engaging with the body 2122of first member 2108. A nut 2162 may be threadably connected to theshaft 2136. A bearing 2164 may be connected to shaft 2136 and provide atransition from rotating portion 2144 to translating portion 2138.

Similarly, the translating portion 2138 of the second member 2112 maylikewise be modular. The translating portion 2138 may include a bearinghousing 2164 that provides rotating engagement with the bearing 2164 toprovide the transition between rotation and translation of the rotatingportion 2144 to pure translation of the translating portion 2138 of thesecond member 2112. A stem 2137 may be rigidly connected by, forexample, a threaded connection to bearing housing 2164.

As shown in FIG. 100, an adaptor 2148 may include an end 2168 whichengages with upper face 2170 of the first component or proximal body2102. The stem 2137 of the translating portion 2138 of the second member2112 includes internal threads 2172 which engage with external threads2174 formed on distal stem or second component 2106 of the prosthesis2104.

As shown in FIG. 100, as the stem 2137 is advanced in the direction ofarrow 2174, the second component 2106 is advanced in the direction ofarrow 2174 with respect to the first component 2102, thereby locking theexternal taper 2130 of the second component 2106 to the internal taper2128 of the second component 2102.

Referring now to FIG. 76, the assembly tool 2100 is shown in aperspective view. To assist in providing fast initial connection of theassembly tool 2100 to the prosthesis 2104, the body 2122 of the firstcomponent 2108 may include a window 2176 formed in the body 2102. Thewindow 2176 may provide access to the bearing housing 2166 so that thebearing housing 2166 may be rotated in the direction of arrow 2168 suchthat the threads 2172 on the stem 2137 may be threaded into theprosthesis 2104 to engage the assembly tool 2100 into the prosthesis2104.

Referring now to FIG. 77, the assembly tool 2100 is shown in a partiallydisassembled or exploded condition. As shown in FIG. 77, it should beeasily appreciated that the various components of the assembly tool 2100may be individually placed in a sterilization equipment such that theassembly tool 2100 may be cleaned between its successive uses insurgeries.

Referring now to FIG. 78, the body 2122 of the assembly tool 2100 isshown in greater detail. The assembly tool 2100 is easily disassembledso that the body 2122 may be separately sterilized or autoclaved. Thebody 2122 includes the transverse window 2176 as well as thelongitudinal opening 2124 to which the internal threads 2116 are formedadjacent upper end 2178 of the body 2122. Internal threads 2180 arepositioned in the body 2122 adjacent the opening 2124 at lower end 2182of the body 2122. The internal threads 2180 engage with the end cap 2146to secure the end cap 2146 to the body 2122.

Referring now to FIGS. 79, 80 and 81, the second member 2112 is shown ingreater detail. The second member 2112 includes the translating portion2138 which includes the stem 2137 as well as the bearing.

Referring now to FIGS. 79-89, the second member 2114 including thetranslating portion 2137 and the rotating portion 2144 are shown ingreater detail, as sub-assemblies, and as individual components.Referring now to FIG. 79, the second member 2114 is shown includingtranslating portion 2137 and rotation portion 2144.

Referring now to FIG. 80, the translating portion 2137 and the rotatingportion 2144 of the second member 2114 are shown in cross-section. Therotating portion 2144 includes the shaft 2136 onto which nut 2162 isthreadably attached. The nut 2162 may further be secured to the shaft2136 by a nut dowel 2178. The bearing 2146 may be threadably secured tothe shaft 2136. The bearing 2164 may be further secured to the shaft2136 by a bearing dowel 2182.

The bearing dowel 2182 lockably secures the bearing 2164 to the shaft2136. The bearing 2164, as shown in FIG. 80, is positioned between thestem 2137 and the bearing housing 2166. The bearing housing 2166, asshown in FIG. 80, may be threadably engaged with the stem 2137 byexternal threads 2182 formed on the stem 2137 which engage with internalthreads 2184 formed on the bearing housing 2166. To provide rotationalmovement of the rotating portion 2144 with respect to the translatingportion 2137, the bearing 2164 includes opposed bearing races 2186 whichmate with bearing races 2186 formed on the bearing housing 2166 and thestem 2137. Bearing balls 2188 cooperate with the bearing races 2186 topermit rotation of the rotating portion 2144 with respect to thetranslating portion 2137.

Referring now to FIG. 81, the second member 2112 is shown in an explodedview with the various components shown separated. It should beappreciated that the second member 2112 may be easily cleaned orsterilized by any commercially available sterilization techniques, suchas autoclaving.

Referring now to FIGS. 82 and 83, the stem 2137 of the translatingmember 2138 that is a part of the second member 2112 is shown in greaterdetail. The translating member 2138 includes the bearing race 2186 torotatably cooperate with the bearing 2164 of FIG. 80 and externalthreads 2182 to lockably threadably engage with bearing housing 2166(see FIG. 80).

Referring now to FIGS. 84 and 85, the bearing housing 2166 is shown ingreater detail. The bearing housing 2166 includes internal threads 2184that threadably engage the bearing housing 2166 with the stem 2137 (seeFIG. 80). The bearing housing 2166 further includes a clearance opening2190 which provides clearance between the bearing housing 2166 and theshaft 2136 (see FIG. 80).

Referring now to FIGS. 86 and 87, the rotating portion 2144 of thesecond member 2112 is shown in greater detail. The rotating portion 2144includes the shaft 2136 that is fixedly secured to bearing 2164 byexternal threads 2192 formed on the shaft 2136 that mate with internalthreads 2194 formed on the bearing 2164. Bearing races 2186 formed inthe bearing 2164 cooperate with balls 2188, (see FIG. 80), to permitrotation of the rotating member 2144 with respect to the translatingportion 2137.

Referring now to FIGS. 88 and 89, the nut 2162 is shown in greaterdetail. The nut 2162 includes a cavity 2196 for receiving the shaft2136. The nut 2162 may be threadably engaged with the shaft 2136 or, asan alternative to the threads. The nut 2162 may be connected to shaft2136 by nut dowel 2178 which is fitted into transverse aperture 2198formed in the nut 2162. The nut 2162 may include an external periphery2199 sized for a standard hexagonal socket for a tool to rotate theassembly tool 2100.

Referring now to FIGS. 90 and 91, the end cap 2146 of the first member2108 of the assembly tool 2100 is shown in greater detail. End cap 2146includes external threads 2111 that engage with the internal threads2182 of the body 2122 of FIG. 78. The end cap 2146, as shown in FIG. 91,may include an exterior groove 2113 for assisting in receiving theadaptor 2148 (see FIG. 100).

Referring now to FIGS. 92 and 93, the handle 2120 of the first member2108 of the assembly tool 2100 is shown in greater detail. The handle2120 includes handle extension 2159 as well as handle post 2158. Thehandle post 2158 may include external threads 2115 for cooperation withinternal threads 2117 formed in body 2122 (see FIG. 78). The handle post2158 may include a bayonet lock 2119 for cooperation with a matingbayonet lock 2121 formed in the handle extension 2159. The bayonet lockof 2119 serves to provide for easy sterilization of the assembly tool2100.

Referring now to FIGS. 94 and 95, the assembly tool 2100 is shown in anassembled condition with the external parts exposed in FIG. 94 and incross-section in FIG. 95.

Referring now to FIGS. 96, 97 and 98, the prosthesis 2104 is shown inposition for use with the assembly tool 2100 of the present invention.

Referring now to FIG. 96, the prosthesis 2104 includes the firstcomponent 2102 in the form of a proximal body, including an internalcavity 2123 that defines the interior taper 2128 which mates withexternal taper 2130 formed on second component 2106 or distal stem 2106.The prosthesis 2104 may further include a recessed nut 2125 that may beused to assure the securement of the first component 2102 to the secondcomponent 2106.

Referring now to FIG. 97, an alternate embodiment of the prosthesis 2104is shown as prosthesis 2104A which includes distal stem 2106A which issimilar to the distal stem 2106 of FIG. 96 and a proximal body 2102Athat is somewhat different from the proximal body 2102 of the prosthesis2104 in that the proximal body 2102A of the prosthesis 2104A has arecess for receiving an external nut 2125A.

Referring now to FIG. 98, the proximal body 2102 is shown in position onthe distal stem 2106 to form prosthesis 2104. As shown in FIG. 98, theinternal taper 2128 of the proximal body 2102 engages with externaltaper 2130 of the distal stem 2106 to form the prosthesis 2104.

Referring now to FIG. 99, the prosthesis 2104 is shown installed incavity 2131 formed in a long bone, for example, femur 2133.

Referring now to FIGS. 102 and 103, the assembly tool 2100 is shown withthe adaptor 2148, shown in phantom, in position over stem 2137 of theassembly tool 2100. As shown in FIG. 102, the adaptor 2148 is slide-ablyreceived over stem 2137 and a spring 2141 in the form of, for example,an internal doughnut shaped helical spring, is matingly fitted betweeninternal groove 2113 formed in the end cap 2146 and internal groove 2143formed in the adaptor 2148. Step end 2168 of the adaptor 2148 is fittedagainst end 2170 of the proximal body 2102 and the nut 2162 is rotatedin the direction of arrow 2160 such that the stem 2137 is advanced inthe direction of arrow 2161 to advance the distal stem 2106 intoengagement with the proximal body 2102.

Internal threads 2172 formed in the stem 2137 are threadably engagedwith external threads 2134 of the distal stem 2106 by manually rotatingthe bearing housing 2166 in the direction of arrow 2145 such that thestep end 2168 of the adaptor 2148 is urged against end 2170 of theproximal body 2102. Such pre-tightening is done prior to the rotation inthe direction of arrow 2160 of the nut 2162.

Referring now to FIG. 103, the first adaptor 2148 is shown in greaterdetail. The first adaptor 2148 includes a longitudinal opening 2147.

Referring now to FIGS. 104 and 105, it should be appreciated that toprovide an assembly tool 2100 that is applicable for a variety ofdifferent sizes and shapes of modular prostheses, the assembly tool 2100may include modular components that are easily changed such that acommon assembly tool may cooperate with prostheses that are modular andhave components of different size.

For example, and according to the present invention and referring toFIG. 104, the assembly tool 2100 may include a second adaptor 2148A thatis different than the adaptor 2148 of FIG. 102 in that the adaptor 2148Ahas an overall length L3 which is shorter than the overall length L4 ofthe adaptor 2148. The shorter adaptor 2148A may cooperate with a secondproximal body 2102A that has a height H3 which is less than the heightH4 of the proximal body 2102.

As shown in FIG. 104, the adaptor 2148A slide-ably fits over stem 2137and includes an internal groove 2143A that receives a doughnut shapedinternal helical spring 2141A which mates with external groove 2113 ofthe end cap 2146 of the assembly tool 2100. The second adaptor 2148A isshown in phantom in FIG. 104. The second adaptor 2148A includes a stepend 2168A which fits against end 2170A of second proximal body 2102A.The second proximal body 2102A may fit to, for example, distal stem 2106or fit to a distal stem having a different size and shape. The stem 2106is fitted to the second proximal body 2102A in a method similar to thatdescribed with FIG. 102.

Referring now to FIG. 105, the second adaptor 2148A is shown in greaterdetail. The second adaptor 2148A includes a longitudinal opening 2147Afor clearance with stem 2137 of the assembly tool 2100.

Referring now to FIGS. 106 and 107, the assembly tool 2100 may beadapted for a third and different proximal body 2102B. The thirdproximal body 2102B may be utilized with the assembly tool 2100 byproviding a third adaptor in the form of third adaptor 2148B. The thirdproximal body 2102B may cooperate with distal stem 2106 or utilize adistal stem with a different size and shape.

Referring now to FIG. 106, the third proximal body 2102B includes a stepface 2170B which mates against step end 2168B of third adaptor 2148B.The internal threads 2172 of the stem 2137 of the assembly tool 2100threadably engage external threads 2134 of the distal stem 2106. Thedistal stem 2106 is engaged to the proximal body 2102B in a similarmanner to that described with FIG. 102. The proximal body 2102B includesa longitudinal opening 2145B which is in clearance with the longitudinalopening 2147B of the adaptor 2148B.

The third adaptor 2148B has a length L5 which is somewhere between thelength L4 of the first adaptor 2148 and the length L3 of the secondadaptor 2148A. Similarly, the third proximal body 2102B has a height H5which is between the height H4 of the first proximal body 2102 and theheight H3 of the second proximal body 2102A.

Referring now to FIG. 107, the third adaptor 2148B is shown in greaterdetail. The third adaptor 2148B includes an internal groove 2143B forreceiving internal doughnut shaped helical spring 2141B. The internaldoughnut shaped helical spring 2141B mates with external groove 2113formed in end cap 2146 of the assembly tool 2100. The third adaptor2148B may thus be quickly snapped into position by inserting the thirdadaptor 2148B upwardly along longitudinal axis 2110 of the first member2112. The third adaptor 2148B includes a longitudinal aperture 2147B forclearance fitting with stem 2137.

Referring now to FIG. 108, the assembly tool 2100 is shown in theassembled condition.

Referring now to FIG. 101, yet another embodiment of the presentinvention is shown as the method of performing surgery 2200. The method2200 includes a first step 2210 which includes the steps of providing aplurality of prostheses. Each prosthesis includes a first component anda second component removeably attached to the first component. At leastone dimension of one of the first and second components of eachprosthesis being different from that of the other prostheses.

The method 2200 includes a second step 2212 of providing an instrumenthaving a first member operably associated with the first component. Thefirst member includes a first member relative motion feature and a bodydefining a generally cylindrical longitudinal opening in the body. Theinstrument also includes a second member operably associated with thesecond component. The second member is operably associated with thefirst member for relative motion between the first and second member forassembly of the first component of the prosthesis to the secondcomponent of the prosthesis. The instrument includes a plurality ofadaptors, each adaptor suited for one of the different prostheses.

The method 2200 further includes a third step 2214 of selecting of oneof the plurality of prostheses and a fourth step 2216 of assembling thefirst component of the one prosthesis to second component of the oneprosthesis. The method 2200 further includes a fifth step 2218 ofassembling the adaptor suited for the one prosthesis from the pluralityof adaptors onto the instrument. The method also includes a sixth step2220 of connecting the first member of the tool to the first component.

The method further includes a seventh step 2222 of connecting the secondmember of the tool to the second component and an eighth step 2224 ofrotating the first member of the tool with respect to the second memberof the tool to secure the first component to the second component.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions, andalterations can be made therein without departing from the spirit andscope of the present invention as defined by the appended claims.

What is claimed is:
 1. A method for performing joint arthroplastycomprising: selecting a first component and a second component for aprosthesis, the first component including a bore defining a bore axis,the second component including a stem defining a stem axis, the stembeing configured to be received in the bore; positioning the firstcomponent of the prosthesis in engagement with a first member of anassembly tool, the first member including a longitudinal openingdefining a longitudinal axis, the first member and the first componentbeing positioned with the longitudinal axis aligned with the bore axis;positioning a second member of the assembly tool in engagement with thesecond component, the second member including: a drive shaft rotatablysupported on the first member for rotation about the longitudinal axis;a translating member coupled to the drive shaft and translatablysupported in the longitudinal opening, the translating member beingconfigured to translate along the longitudinal axis as the drive shaftis rotated; a rotatable member rotatably and translatably coupled to thetranslating member within the longitudinal opening of the first memberfor movement along the longitudinal axis with the translating member,the rotatable member being manually rotatable with respect to thetranslating member about the longitudinal axis, wherein rotation of therotatably member with respect to the translating member causes therotatable member to translate along the longitudinal axis with respectto the translating member; and an adaptor stem coupled to the rotatablemember for movement therewith along the longitudinal axis, the adaptorstem extending therefrom out of the longitudinal opening of the firstmember, the adaptor stem including an end configured to be removablyattached to the second component with the stem axis aligned with thelongitudinal axis; extending the end of the adaptor stem into the boreof the first component; removably attaching the end of the adaptor stemto the stem of the second component; and rotating the drive shaft totranslate the translating member, the rotatable member, and the adaptorstem in a direction that causes the second component to move withrespect to the first component toward the longitudinal opening of thefirst member.
 2. The method of claim 1, wherein the bore of the firstcomponent includes an internal taper and the stem of the secondcomponent includes an external taper, the internal taper and theexternal taper being configured to form a taper connection.
 3. Themethod of claim 2, wherein the rotation of the drive shaft furthercomprises: rotating the drive shaft to translate the translating member,the rotatable member, and the adaptor stem until the internal taper andthe external taper are positioned in engagement with each other to formthe taper connection.
 4. The method of claim 1, wherein the stem has adistal end with external threads, and wherein the end of the adaptorstem includes internal threads configured to threadingly engage theexternal threads of the stem, and wherein removably attaching the end ofthe adaptor stem to the stem of the second component further comprises:positioning the end of the adaptor stem in engagement with the distalend of the stem; and manually rotating the rotatable member with respectto the translating member to threadingly engage the internal threadswith the external threads.
 5. The method of claim 4, wherein therotatable member comprises a thumb wheel.
 6. The method of claim 5,wherein the first member includes at least one window that providesaccess to the thumb wheel located within the longitudinal opening, andwherein manually rotating the rotatable member with respect to thetranslating member further comprises: accessing the thumb wheel throughthe at least one window in the first member to rotate the thumb wheel.7. The method of claim 6, wherein the first member includes an innerwall that defines the longitudinal opening, wherein the inner walldefines recesses that extend along the inner wall in alignment with thelongitudinal axis, and wherein the translating member includes tabs thatare slidably received in the recesses, wherein the translating memberand the drive shaft are threadingly engaged with each other, and whereinthe recesses and the tabs cooperate to prevent the translating memberfrom rotating along with the drive shaft so that the translating memberis translated with respect to the drive shaft via the threadedengagement.
 8. The method of claim 7, wherein the selection of the firstcomponent and the second component further comprises: selecting a firstcomponent from a plurality of first components, each of the firstcomponents having at least one dimension that is different from the restof the first components; and selecting a second component from aplurality of second components, each of the second components having atleast one dimension that is different from the rest of the secondcomponents.
 9. The method of claim 8, further comprising: removablyattaching the first member to the first component via a first memberadaptor.
 10. The method of claim 9, further comprising: selecting thefirst member adaptor from a plurality of first member adaptors, each ofthe first member adaptors being associated with a different firstcomponent from the plurality of first components, the selected firstmember adaptor being associated with the selected first component.
 11. Amethod for performing joint arthroplasty comprising: selecting a firstcomponent from a plurality of first components, each of the firstcomponents having a bore defining a bore axis and having at least onedimension that is different from the rest of the first components; andselecting a second component from a plurality of second components, eachof the second components having a stem defining a stem axis having atleast one dimension that is different from the rest of the secondcomponents, the stem being configured to be received in the bores of thefirst components; selecting a first member adaptor for removablyattaching the first component of the prosthesis to a first member of anassembly tool, the first member including a longitudinal openingdefining a longitudinal axis, the first member adaptor being selectedfrom a plurality of first member adaptors, each of the first memberadaptors being associated with a different first component from theplurality of first components and configured to removably attach theassociated first component with the first member of the assembly toolwith the longitudinal axis aligned with the bore axis, the selectedfirst member adaptor being associated with the selected component;removably attaching the first member to the selected first component viathe selected first member adaptor; positioning a second member of theassembly tool in engagement with the second component, the second memberincluding: a drive shaft rotatably supported on the first member forrotation about the longitudinal axis; a translating member coupled tothe drive shaft and translatably supported in the longitudinal opening,the translating member being configured to translate along thelongitudinal axis as the drive shaft is rotated; a rotatable memberrotatably and translatably coupled to the translating member within thelongitudinal opening of the first member for movement along thelongitudinal axis with the translating member, the rotatable memberbeing manually rotatable with respect to the translating member aboutthe longitudinal axis, wherein rotation of the rotatably member withrespect to the translating member causes the rotatable member totranslate along the longitudinal axis with respect to the translatingmember; and an adaptor stem coupled to the rotatable member for movementtherewith along the longitudinal axis, the adaptor stem extendingtherefrom out of the longitudinal opening of the first member, theadaptor stem including an end configured to be removably attached to thesecond component with the stem axis aligned with the longitudinal axis;extending the end of the adaptor stem into the bore of the firstcomponent; removably attaching the end of the adaptor stem to the stemof the second component; and rotating the drive shaft to translate thetranslating member, the rotatable member, and the adaptor stem in adirection that causes the second component to move with respect to thefirst component toward the longitudinal opening of the first member. 12.The method of claim 11, wherein the bore of the first component includesan internal taper and the stem of the second component includes anexternal taper, the internal taper and the external taper beingconfigured to form a taper connection.
 13. The method of claim 12,wherein the rotation of the drive shaft further comprises: rotating thedrive shaft to translate the translating member, the rotatable member,and the adaptor stem until the internal taper and the external taper arepositioned in engagement with each other to form the taper connection.14. The method of claim 11, wherein the stem has a distal end withexternal threads, and wherein the end of the adaptor stem includesinternal threads configured to threadingly engage the external threadsof the stem, and wherein removably attaching the end of the adaptor stemto the stem of the second component further comprises: positioning theend of the adaptor stem in engagement with the distal end of the stem;and manually rotating the rotatable member with respect to thetranslating member to threadingly engage the internal threads with theexternal threads.
 15. The method of claim 14, wherein the rotatablemember comprises a thumb wheel.
 16. The method of claim 15, wherein thefirst member includes at least one window that provides access to thethumb wheel located within the longitudinal opening, and whereinmanually rotating the rotatable member with respect to the translatingmember further comprises: accessing the thumb wheel through the at leastone window in the first member to rotate the thumb wheel.
 17. The methodof claim 16, wherein the first member includes an inner wall thatdefines the longitudinal opening, wherein the inner wall definesrecesses that extend along the inner wall in alignment with thelongitudinal axis, and wherein the translating member includes tabs thatare slidably received in the recesses, wherein the translating memberand the drive shaft are threadingly engaged with each other, and whereinthe recesses and the tabs cooperate to prevent the translating memberfrom rotating along with the drive shaft so that the translating memberis translated with respect to the drive shaft via the threadedengagement.